The Arup Journal The Arup Issue 1 2015 The Arup Journal About Arup

Arup is a global organisation of designers, Arup’s core values drive a strong culture Printed by Pureprint Group using engineers, planners, and business of sharing and collaboration. their ® environmental print consultants, founded in 1946 by Sir Ove technology. The printing inks are made from vegetable based oils and Arup (1895-1988). It has a constantly All this results in: no harmful industrial alcohol is used evolving skills base, and works with local a dynamic working environment that in the printing process with 98% of and international clients around the world. any dry waste associated with this inspires creativity and innovation production diverted from landfill. ® a commitment to the environment and the Pureprint Group is a CarbonNeutral Arup is owned by Trusts established for the company and is certificated to benefit of its staff and for charitable communities where we work that defines Environmental Management purposes, with no external shareholders. our approach to work, to clients and System ISO 14001 and registered This ownership structure, together with the collaborators, and to our own members to EMAS, the Eco Management and Audit Scheme. core values set down by Sir Ove Arup, robust professional and personal networks are fundamental to the way the firm is that are reinforced by positive policies on organised and operates. The Arup Journal equality, fairness, staff mobility, and Vol50 No1 (1/2015) knowledge sharing Editor: Angela Swann Independence enables Arup to: Designer: Nigel Whale the ability to grow organically by attracting shape its own direction and take a long- Editorial: Tel: +44 (0)20 7755 4838 and retaining the best and brightest email: [email protected] term view, unhampered by short-term individuals from around the world – and pressures from external shareholders Published by Global Marketing from a broad range of cultures – who share and Communications, distribute its profits through reinvestment those core values and beliefs in social Arup, 13 Fitzroy Street, in learning, research and development, to usefulness, sustainable development, and London W1T 4BQ, UK. Tel: +44 (0)20 7636 1531 staff through a global profit-sharing excellence in the quality of our work. Fax: +44 (0)20 7580 3924 scheme, and by donation to charitable All articles ©Arup 2015 organisations. With this combination of global reach and a collaborative approach that is values-driven, Arup is uniquely positioned to fulfil its aim to shape a better world. Issue 1 2015

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93780_Cover.indd 1 22/05/2015 10:32 93780_Cover.indd 2 22/05/2015 10:32 Contents

4 Melbourne Regional Rail Link Jonathon Parker Rachel Nicholls Sinead Collins Rob Turk Paul Carter Kym Burgemeister

14 Stormen – art and music in the Arctic James Beer Matt Atwood William Algaard George Ellerington Ian Knowles

24 Singapore Sports Hub Andrew Henry Chia Wah Kam Clive Lewis Malcolm Smith Mike King Nick Boulter Peter Hoad Ruth Wong Scott Munro See Lin Ming

52 Bosco Verticale – a forest in the sky Luca Buzzoni James Hargreaves Valeria Migliori

60 UCSF Medical Center at Mission Bay Alisdair McGregor Raj Daswani

In The Arup Journal, 2/2014, the introduction to the article ‘Our inheritance, the next step?’ by the late Sir Philip Dowson (re-published in his memory) omitted to note that the fourth founder-partner of Arup Associates in 1963 (with Dowson, Sir Ove Arup and Derek Sugden) was Ronald Hobbs (1923-2006). ‘Bob’ Hobbs, as he was universally known, later became Chairman of Arup Associates (1981-84) and Co-Chairman with Sir Jack Zunz of Ove Arup Partnership (1984-89).

Front cover: Singapore Sports Hub is a new feature on the city’s skyline. Photo: Darren Soh. Left: Melbourne Regional Rail Link involved building new tracks leading into Southern Cross Station, Melbourne. Photo: Regional Rail Link Media Library.

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93780_Text.indd 3 22/05/2015 10:34 Melbourne Regional Rail Link

Authors Jonathon Parker Rachel Nicholls Sinead Collins Rob Turk Paul Carter Kym Burgemeister

Introduction The Regional Rail Link (RRL) in Existing stations To Bendigo, Sunbury, To Upfield Melbourne is one of the largest public Existing rail network Sydenham To Craigieburn transport projects ever undertaken in Regional Rail Link new tracks To Ballarat, Australia. It has transformed the rail Existing tracks Footscray Melton network and created capacity for an extra New stations Tottenham South Kensington 23 metropolitan and 10 regional services Deer Park Ardeer Station rebuild during each morning and evening peak. Sunshine Station upgrades Middle Footscray Major station upgrades West Footscray Appointed as the client’s technical advisor in North Melbourne a joint venture with KBR, called KAJV, Southern Cross Arup played a pivotal role in providing technical services from concept design Tarneit through to construction and operation. This article looks at what RRL means for

Melbourne and the challenges of building it, WyndhamV Vale focusing on what KAJV did to ensure successful delivery. PORT PHILLIP BAY

RRL was honoured with Infrastructure Partnerships Australia’s ‘Infrastructure Werribee N Project of the Year’ award in 2014 and will To Geelong become fully operational in June 2015. 2.

Setting the scene The brief Municipalities in western Melbourne are The Regional Rail Link Authority (RRLA), amongst the fastest growing per capita formed in 2009, was briefed to deliver a new anywhere in Australia, far outstripping the pair of regional tracks from Southern Cross growth of traditionally more densely Station to the outer western suburb of Melbourne populated areas to the south and east of the Werribee, via the suburbs of Footscray, city. Additionally, there has been steady and Sunshine and Deer Park (Fig 2). substantial increase in demand for train services from regional Victoria. Passenger Approximately 45km long, the tracks were volumes for regional train operator V/Line to be built along mixed brownfield and are currently at 60-year highs (Fig 1). greenfield sites with stations along the 1. corridor being either newly built or In 2006 the government commissioned a substantially modified. Major structures study to look at transport solutions for would include river crossings, road-rail Victoria. The study recommended grade separations and rail-rail flyovers. constructing a new pair of regional tracks Urbanised area Metropolitan urban boundary between Melbourne’s largest station, Regional and metropolitan trains would no 50km radius Southern Cross, and the city’s outer-west. longer use the same tracks, improving In 2009, federal funding was secured and a reliability, travel times and frequency of budget approved for the project. services across the network. The new tracks would service Victoria’s three most populated rural centres – Geelong, Ballarat, and Bendigo – with trains from Geelong diverting along a new 26km corridor before connecting to the existing track which already serviced trains from Ballarat.

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93780_Text.indd 4 22/05/2015 10:34 1. Melbourne’s urbanised area is 4. A new pair of regional tracks rapidly expanding westward. was aligned into an existing rail 2. The route of the Regional Rail corridor in North Melbourne. Link reflects population growth 5. Detailed analysis ascertained west of the city. optimum clearance from bridges 3. Road over rail grade separations achievable on this route. were a key feature of the greenfields section of the project.

With the brief established, RRLA needed a technical partner. In late 2009 KAJV was appointed to provide concept designs for the entire corridor. On successful delivery, the design scope was extended to delivery of reference designs, procurement and other technical advisory services throughout the construction phase of the project.

Track design Creating free flowing regional and suburban services into and out of Southern Cross Station meant removing several bottlenecks on the network to enable regional trains to 3. travel at speeds of up to 160km, with a theoretical headway of only two minutes during peak times. As a result, alignment of the tracks was set out to minimise conflict between the regional, suburban and freight services. Three new rail-over-rail grade separations were required and one was to be fully refurbished.

Equally critical to the task was aligning the new pair of regional tracks into the already congested rail corridor. Much of the corridor was too narrow to lay new tracks without impinging on the existing rail corridor boundaries. At many locations, existing tracks were slewed to one side to create the additional space needed (Fig 4).

4. Elsewhere, where land acquisition of properties adjacent to the corridor was Underside of bridge unavoidable, the acquisition process was progressed to facilitate the construction programme. KAJV’s concept designs were relied on heavily to determine the extent of the necessary land aquisition.

Design standards that impacted alignment of the tracks such as clearances to structures, track radius and signals location, were systematically reviewed. Where full constraints could not be fully complied with, a rigorous validation process was followed (Fig 5).

Through freight line RRL down RRL up

5. Static envelope Kinematic envelope for Maximum kinematic envelope for all tangent track only cant and track curvature effects

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93780_Text.indd 5 22/05/2015 10:34 Footscray Activity Precinct

Newells Paddock Urban Nature Reserve

Footscray Station New West Footscray Josephs Road Viaduct Station (relocated) Precinct Whitten Hopkins Street Rail/rail flyover Oval Irving Street Melbourne Middle Footscray Sunshine Station Bunbury Street Tunnel Kensington Road Sunshine Road

RRL lines (B.G) 6. Buckley Street ARTC lines (S.G) Werribee lines (B.G) Geelong Road Rail over Sydenham lines (B.G) road New station Bridge lengthening

Maribyrnong New bridge River Corridor widening Albert Street Victoria Street Footscray Activity New Nicholson Street Precinct number West Footscray Station (relocated) Geelong Middle Road Footscray Station Footscray Station Maribyrnong River

Quaternary basalt

Sand and clay

At grade Cutting At grade Cutting Viaduct

~3300m

7. 6. Track alignment through Footscray navigated constraints including seven road-rail and rail-rail grade separations and three stations. 7. West Werribee Junction where the new tracks join the existing Geelong line. 8. Yellow girders for Dudley Street Rail Bridge came to symbolise the start of the project.

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93780_Text.indd 6 22/05/2015 10:34 KAJV’s recommended solutions were critical to informing discussions and decisions to determine the most appropriate alignment (Fig 6).

Beyond Melbourne’s sprawling suburbs the track alignment was more straightforward. The new 26km rail corridor extends south west from the outskirts of the city’s western suburbs to tie-in with an existing rail corridor at Werribee.

Ground conditions and geotechnical challenges The alignment of the new tracks passes through the basaltic plains of western Melbourne and across significant thicknesses of soft alluvial deposits associated with the Maribyrnong and Yarra river systems.

The basaltic plains are defined by high- strength Quaternary basalt, typically 15m to 30m thick, overlying Tertiary sands and clays. Three new cuttings through the high-strength basalt were required along the 8. rail line to create road-rail grade separations and maximise efficiency of both road and rail operations. However, some of the new tracks for RRL published reference documents, was taken were to be located in an area of the rail into account together with the historic At the concept stage of the project, KAJV corridor never exposed to train loading so loading associated with the rail corridor. investigated the effectiveness of excavation the design of the new track bed had to through the high strength rock by carrying address the issues of: Civil structures out blast assessments to determine potential The project involved construction of more patterns and weights of explosive charge. Excavating into very soft silts and the than 50 new bridges. KAJV developed Limiting ground vibration and air over-blast construction challenges this would present concept designs for both new and modified pressure to acceptable values for adjacent Disposal of excavated silt which, due to its bridge structures including detailed design residential properties was a critical element classification as an Acid Sulphate Soil, for programme-critical structures such as of this assessment, so contour mapping would need to be taken to a regulated Dudley Street Rail Bridge. within a GIS model was an integral part of disposal facility the blast assessment analysis. Dudley Street Rail Bridge The likely settlement of the track bed over This was the first significant structure to be The rail alignment approaching Southern time due to settlement of silt under the new built on the project. Located just outside Cross Station is underlain by very soft train loading. Southern Cross Station, it carries Coode Island Silt (CIS). This soil stratum is metropolitan and freight by-pass tracks widespread across the western end of the The approach to the design of the new track over Dudley Street (Fig 8). The bridge set city and it has dictated deep piling solutions bed, therefore, was to minimise its thickness the benchmark for design documentation, for much of Melbourne’s docklands. to avoid excavation into the CIS whilst application of the rail authorities’ standards maintaining the required long-term and quality of construction for the RRL The historic development of the existing performance of the rails. project. tracks within this soft soils area has been based on re-ballasting and re-levelling the To demonstrate the performance of the new With a clear span of 38.25m, its track bed as the underlying CIS settled in track bed, a series of finite element analyses superstructure consists of two twin half response to train loading. Over many were carried out to model the distribution of through girder bridges. These are formed decades, this had locally improved the load from train wheels through rail, sleepers from 2.57m-deep steel plate girders and properties of the CIS below the tracks and, and ballast (3D analyses) and the overall 350WC197 transverse beams made over time, required maintenance of the impact of this loading on the compression of composite with a 230mm concrete slab. tracks had become less frequent in response the CIS, and hence track settlement over Its substructure consists of two in-situ to track settlement. time (time-dependent 2D analyses). concrete abutments each supported on six Modelling of the in-situ properties of the bored concrete piles. CIS was a key parameter for these analyses. Laboratory test data, both site specific and

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93780_Text.indd 7 22/05/2015 10:34 Three key constraints influenced the design and structural form of the bridge:

1. Rail tracks adjacent to the bridge were fully operational during construction and rail occupations were limited to two weekends during the construction period. This limitation led to the adoption of a steel superstructure. 2. The bridge is located parallel to two existing concrete rail bridges at Dudley Street which were once part of a series of rail bridges supported on timber piled brick piers and abutments. The location of the timber piles and their structural condition could not be assessed during the design phase due to road and rail access restrictions so to minimise risk a clear span structure, independent of existing infrastructure, was adopted. 3. The existing road network and 9. carriageway clearances on Dudley Street had to be maintained below the new Hopkins Street Bridge large precast concrete corbel onto the back structure. This clearance restriction led to The challenges of widening the existing rail of the new central pier. High-strength steel the development of a half through bridge corridor in a constrained brownfield anchor bars combined with steel spreader structure. environment led to a range of innovative plates were suggested to attach the new concept design solutions. corbel on to the back of the central pier, Steelwork fabrication and installation was thus providing the necessary load capacity carried out by Macfab (Melbourne, Victoria) In the case of Hopkins Street Bridge, which for the new span. with Samaras (Adelaide, South Australia) services one of the busiest roads in the area, acting as a sub-fabricator. A full trial full removal and replacement of the single- To keep Hopkins Street open to traffic during assembly of the bridge was undertaken in span steel composite bridge was considered modification works, the concept design Samaras’ Workshop in Adelaide: this unfeasible by the roads authority. Options allowed for staged construction. This meant ensured fit-up of the end plates bolt holes of suggested included creating a temporary that works could proceed to one side of the each transverse beam with the plate girder bridge or placing a new bridge over the bridge deck while traffic flows were diverted web bolt holes and allowed the packer plate existing bridge. After a process of around. The concept design also allowed for at each connection to be machined to stakeholder engagement, the proposal top down construction which meant the achieve fit tolerance. eventually adopted was to add a span onto bridge deck was installed prior to completion the back of the bridge effectively converting of excavation below the deck. Disruption to The 39m-long plate girders were it from one span to two. traffic flows could be reduced by re-opening transported – each on a single truck, as sections of the bridge to traffic, despite complete elements – under police escort This unconventional design meant excavation beneath the bridge being still in from Adelaide to Melbourne, the transverse converting the existing northern abutment progress. This unusual concept design beams making the same journey on several into a new central pier to support the new proved an effective solution and was largely other trucks. span. The concept design proposed placing a adopted in the final design (Fig 10).

The steelwork was lifted into position using a 350T crane in a single weekend of rail occupation then pre-cast concrete panels, 10. Existing deck New deck acting as permanent formwork to the

concrete deck, were lifted into position in a Compact fill New abutment separate weekend rail occupation. The Existing abutment New corbel remainder of the works were completed while rail tracks adjacent to the bridge were Shotcrete with Rock bolts Steel plate rock bolts as required fully operational. strengthening to both sides New track Basalt

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93780_Text.indd 8 22/05/2015 10:34 9. Anderson Road: challenges 11. Precast prestressed concrete Grade separations at this brownfield grade separation is the established method of KAJV carried out concept designs for all included minimising rail and construction for this type of road disruption and relocating bridge in Australia. 16 new road-rail grade separations along the length of the project, the majority of which major services. 12. Ballan Road: a typical 10. The design of Hopkins Street two-span rail-under-road grade consisted of precast, prestressed concrete was unconventional but it meant separation in the greenfield ‘super tee’ superstructures. This form of the bridge stayed open throughout environment. construction is common in Australia and is construction. preferred by contractors for its speed of erection, versatility of design and well

CL CL CL CL established design and construction 11. Track Track Track Track methodologies.

Span lengths varied between approximately 14m and 35m. The longest span resulting in

Abutment bearing Traffic lane a beam depth of 1800mm. Substructure construction was typically cast in-situ 12.3m Traffic lane concrete columns with bored piled foundations. Reinforced earth walls were Reinforced Shared user path retaining wall typically proposed for the abutments (Figs 11–12).

Two existing level crossings at Anderson

CL CL Road in the brownfield environment Abutment bearing Abutment bearing presented a different set of challenges. 35.2m 4.0m Underground services, in particular, required careful attention. At one grade separation,

Approach for example, lowering the road meant the slab relocation of the main aviation fuel pipeline CL CL CL CL Reinforced servicing Melbourne Airport to retaining wall 0.6m diameter accommodate this (Fig 9). columns

12.

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93780_Text.indd 9 22/05/2015 10:34 13. RRL provides critical infrastructure to support growing demands for rail travel in regional Victoria. 14. The inclusion of a new temporary station at Albion Station was modelled as part of the bus replacement strategy.

This information was used to evaluate traffic performance and improvement options for the proposed level crossings.

Replacement bus strategy As well as planning the permanent design of the RRL, KAJV informed key elements of 13. construction works planning.

Subway Subway Particularly challenging was developing a Express bus Express bus boarding area boarding area strategy to fully close the rail corridor for all Bus 1 train services between Deer Park Station and Bus 1 Footscray Station to allow completion of Bus 2 early works within the rail corridor. Closing Bus 2 Bus 3 Train on this line would impact approximately 18,000 platform 2 passengers each day so an effective strategy Bus 4 Bus 3 for maintaining passenger movement was required. From a transport perspective, it Bus 4 involved transferring passengers from Albion Station to buses which would take 00:01:15 00:01:00 them to Flemington Station where they could use a separate rail line to complete their 14. journey to the city.

Strategic framework and travel KAJV used this information to inform The study identified improvements demand forecasting capacity requirements for pedestrians at required for this to happen including: During the initial stages of project stations, demand for car parking, and traffic Changes to key stations to allow safe development and concept design, KAJV capacity requirements at intersections and boarding and alighting established a strategic framework identifying level crossings. key transport considerations along the length Transport interchange infrastructure of the rail corridor. An important component Travel demand forecasting was required modifications and additions. supplemented by further studies, as well as was the development of travel demand Number of buses needed to transport discussions with RRLA and key forecasts using the Department of passengers between Albion and stakeholders, to identify bus stops required Transport’s ‘Melbourne Integrated Transport Flemington Station Model’ (MITM). for stations along the corridor, short and long term parking needs and the design of a 26km The impacts of running a large number Working with RRLA and the Department of shared path cycling route from Werribee to of buses along the road network. Transport, KAJV refined and enhanced Deer Park. MITM to better represent travel demand The findings were used to inform associated with current regional train Level crossing traffic performance construction of a temporary bridge and services and the specification of future assessment transport interchange at Albion Station transport networks (e.g. planned road and Safe and efficient operation of road crossings (Fig 14) and a transport interchange at rail projects), as well as testing potential of the rail corridor was fundamental to the Flemington Station, as well as providing key future train operational scenarios for both concept design. KAJV carried out a series of information to plan the bussing operation. RRL and metropolitan services. studies to understand traffic performance at Successfully implemented on a number of the five level crossings between Sunshine occasions, the bussing operation was vital in This analysis provided patronage forecasts and Deer Park and developed micro- facilitating construction of the project and, for the proposed RRL and metropolitan simulation traffic models to represent despite some inconvenience for users services and associated road traffic demands. anticipated level crossing operation after overall, it generated very little negative RRL was opened. feedback.

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93780_Text.indd 10 22/05/2015 10:34 Best practice station design Cox Architects worked alongside KAJV to prepare concept designs for the two new stations and major modifications to three existing stations. The KAJV concept designs were used to determine a set of minimum requirements to be incorporated into each station during detailed design.

Footscray Station The main challenges involved replacing the existing car park and forecourt area with an additional two platforms, lengthening the existing concourse, and redesigning the station frontage. Platforms had to be lengthened from 160m to 250m to allow for longer trains.

Various access solutions for the concourse were investigated including ramps, escalators, lifts and stairs. Unsatisfactory elements of the existing station, such as the excessively steep stairs, were examined and 15. improved where possible.

The importance of conserving heritage architecture was taken into account and historical buildings on the platform were preserved and enhanced, while other notable features at concept stage included providing integrated locked bicycle storage and improved access to the nearby shopping precinct and public transport. 16. 17. Sunshine Station The concept design explored options for Wyndham Vale and Tarneit Stations 15. Aerial shot of the new Tarneit removing the notoriously uninviting Reflecting the government’s desire to station with car parks for commuters from the large underpass access to the platforms, replacing provide essential public transport catchment area. infrastructure in the growth areas to the it with a new high-quality concourse. Similar 16. Tarneit Station: KAJV to Footscray, the station facilities included west of the city, the project included two concept design. essential ‘premium station’ elements such as new stations at Wyndham Vale and Tarneit. 17. Tarneit Station: on completion. new ramps, lifts, kiosks, waiting rooms, Built entirely on greenfield sites, these staffing quarters, ticket office and locked stations did not have the same demanding bicycle facilities. The other main feature of physical constraints as stations located in the the concept was the redesign of the existing brownfield environments (Fig15). bus interchange that adjoins the station and is a major transport hub that services up to The concept designs for both new stations 12 different bus routes. The station featured large car parks designed to redevelopment allowed KAJV to investigate accommodate the large projected commuter different bus bay configurations and various catchment in these areas. At Wyndham Vale layouts were proposed that improved the station was built into an extensive cutting efficiency of movement and enhanced safety due to topography and to amenity. In both for pedestrians within the area. cases, the design ultimately built remained highly consistent with the design set out in All stations were designed for the Level 4 the concept phase (Figs 16–17). Green Star rating which is regarded as industry best practice. Station sustainability features included rain water storage tanks, solar panels and water sensitive urban design.

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93780_Text.indd 11 28/05/2015 15:46 Acoustic design The Department of Transport developed a Conclusion Although there was no established railway new Victorian ‘Passenger Rail Infrastructure The RRL is the largest transformation of noise policy in Victoria when work on Noise Policy’ mid-way through the project Melbourne’s railway network in a developing RRL started, the Planning in 2013. This provided a solid policy generation. It will help to open up areas to Minister decided the environmental framework for mitigating railway noise the west of Melbourne and allow them to assessment should include the consideration where it was predicted to exceed prescribed prosper. Removing rail bottlenecks and of any noise impacts. daytime or night-time averages, or overall upgrading stations will benefit communities maximum noise levels. along the line and provide a lasting legacy KAJV started the assessment by building a for the people of Melbourne. computer model using the Nordic Method Sustainability (Kilde) in SoundPlan. However, the lack of The sustainability approach of RRL, from Arup in its joint venture with KBR played a source sound-level data meant the team also design through to construction, has been one key role in successfully delivering RRL. had to embark on the largest rolling stock of its outstanding features, culminating in Working closely with the client over the noise survey ever undertaken in Victoria. the project winning the 2014 Premier of lifetime of the project, Arup brought together Hundreds of individual noise measurements Victoria’s Sustainability Awards for a team of experts spanning a range of were made of the various electric, diesel- Buildings and Infrastructure. disciplines and drew on skills locally and multiple-unit (DMU) and diesel locomotives internationally. The services provided were used on the network. The base noise levels The way sustainability targets were critical to overcoming many of the were then normalised for measurement integrated within the project represented challenges the project faced along the way. distance and number of carriages prior to a step change compared with how linear regression to determine speed-related sustainability targets had traditionally been source noise levels. approached within large infrastructure projects in Australia. 18. At Maribyrnong Crossing in Footscray, the team developed a A key input to the model was the future structural solution sympathetic to railway operating schedule, including This step change emanated from the RRLA’s the heritage-listed truss bridge. detailed understanding of hourly train flows, Sustainability Policy and the associated KAJV prepared concept designs type and number of carriages. The acoustic vision, objectives and targets that KAJV and undertook consultation with were instrumental in forming. key stakeholders including team worked closely with Department of Melbourne Water and Heritage Transport rail planners to devise a Victoria. representative schedule. In addition, The RRLA Sustainability Policy defined 19. The Maribyrnong Crossing is SoundPlan was used to generate noise level seven objectives for the project which were linked by a viaduct on either side. contours and individual noise level to be met by achieving 22 supporting targets. The new adjoining rail-rail grade predictions at thousands of properties A focus of KAJV’s research was to define separation allows RRL tracks to adjacent to the rail corridor and to auralise targets that rewarded an outcome, rather than pass through Footscray Station. potential railway noise levels at a process, leaving responsibility for target representative properties. achievement with each of the relevant design and contracting teams. This research built on Even in the absence of established railway extensive understanding of the sustainability noise criteria, this process proved valuable. opportunities within the infrastructure sector. The acoustic assessment was key to the environmental submissions for the project and the predictions were used to determine whether noise mitigation was necessary at 1972 bridge 1858 bridge 18. various locations near the railway corridor. The preliminary noise mitigation design Newells Paddock was subject to multi-criteria analysis, Urban Nature Reserve Existing approach overseen by Arup’s Management Consulting embankments and Economics group, and the outcome supported the use of noise barriers and glazing treatments in some locations.

Low-profile deck to The resulting RRL noise model was the maximise view of largest, most detailed railway noise central bridge assessment ever undertaken in Australia. Abutment of Single pier new bridge set back to aligned with It encompasses the entire 45 km railway to allow view of 1972 bridge stone abutments corridor from Southern Cross Station, Parapet of existing through Sunshine, Deer Park, Tarneit and adjacent building Wyndham Vale, including all metropolitan, regional and freight movements within Abutment of new bridge set back the corridor. to allow view of stone abutments

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93780_Text.indd 12 22/05/2015 10:34 19.

Authors Martin Beeton, Kelvin Bong, Mark Bridger, Tim Bryant, James Selth, Alex Shah, David Shrimpton, Charles Jonathon Parker is a Senior Engineer. Initially Design Kym Burgemeister, Jeff Burleigh, Paul Carter, Nigel Shum, Daniel Simmonds, Greg Simpson, Colin Sloan, Manager, later seconded to RRLA as Technical Advisor Casey, Argoon Chuang, Daniella Ciavarella, Diana Trent Smith, Julia Smithard, Charles Spiteri, during the delivery phase. Coelho, Liam Cole, Sinead Collins, Matthew Collits, Jayanthiraj Steven, Nathan Stevens, Alex Stewart, Rachel Nicholls is Principal. Geotechnical Team Leader Stacy Conroy, Joseph Correnza, Bob Couzin Wood, Jess Suett, Anna Thiele, Przemyslaw Tomczyk, Tony initially, later assumed role of Project Director. James Crocaris, Steve Dalton, Simon de Lisle, Clive Vidago, Philippe Vienot, Rob Warner, Jen Watson Domone, Barry Drew, Peter Duggan, Trevor Duncan, Stewart Bird, John Wheadon, Leigh Williams, Ashley Sinead Collins is a Senior Engineer. Bridge designer, in Jaime Ericksen, Peter Fanous, David Farrell, Adrian Willis, Jonathan Wright, David Young, Sarah Zhang. particular responsible for Dudley Street Bridge. Fazio, Jared Fetherston, Vincent Fok, Ken Fong, Marco Joint Venture partner: KBR Rob Turk is an Associate and Sustainability Manager. Furlan, Matt Gardiner, Andy Gardner, Hugh Gardner, Paul Carter is a Senior Engineer, Transport Planning Will Gouthro, Chris Graham, Phillip Greenup, Image credits and Technical Leader. Jonathan Griffin, David Hanson, Chris Harrison, Chris 1 The State of Victoria, Department of Transport, Harvey, Gerard Healey, Andrew Herriman, Duncan Planning and Local Infrastructure; 2,5,6,8,10,11,14,18 Kym Burgemeister is an Associate Principal and Hollis, Martin Holt, Greg Hopkins, Min Huang, Peter KAJV; 3,4,7,9,12,13,17,19 Regional Rail Link Media Acoustics Team Leader. Hurlstone, Karim Issa, Perry Jackson, Matt James, Library; 16 Cox Architects. Peter Johnson, Bruce Johnson, Jess Johnson, Callan Project credits Jones, Nick Joveski, Nerissa Kamat, George Client: Regional Rail Link Authority (RRLA) Civil, Kazantzidis, Robin King, Russell Kolmagorov, Stefan civil structural, building structural, transport modelling Konstantinidis, Hannes Lagger, Andy Lewis, Jenny Lo, and planning, GIS, noise and vibration, track, Chris Lyons, Robert Macri, Michele Mangione, John signalling, security, tunnelling, geotechnical, project Mcgain, David Mchugh; Cameron Mcintosh, Sarah management, architectural, landscape architecture, fire, Mcintosh, Mick Mcmanus, Joe Metcalfe, Brendan building services, risk, sustainability, environmental, Molloy, Rachel Nicholls, Judy Nicholson Kelava, hydrology, project office set-up management consulting Gareth O’halloran, James Oakley, Karen Oj, Jonathan and economics: Arup – Prasad Adhava, Niruma Akhter, Osborne, Jin Pae, Gavin Palmer, Jonathon Parker, Joe Sarah Alper, Elisa Anderson, Joseph Anderson, Justin Paveley, Jim Peacock, Kalyan Peddi, Lucy Pike, Derek Arifin, Robert Armstrong, Shobha Baheti, Elmer Powell, Tim Procter, David Riley, Marius Roman, Bandalan, Malcolm Barr, Paul Bartholomew, Hywel Rowlands, Stephanie Sarta, Helen Searle,

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93780_Text.indd 13 22/05/2015 10:34 Stormen - art and music in the Arctic

Location Authors Bodø, Norway James Beer Matt Atwood William Algaard George Ellerington Ian Knowles

1.

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93780_Text.indd 14 22/05/2015 10:34 2.

1. Store Sal – this world-class concert hall converts into an equally effective theatre. 2. Daylight streams through floor-to-ceiling windows that frame a view of the fjord from the library. 3. Stormen seen from the harbour, library in the foreground, concert hall tucked neatly behind.

3.

Introduction DRDH Architects worked in close History, quest and competition A wind-swept harbour in the Arctic Circle is collaboration with Arup on the acoustic and The seeds of Bodø’s quest for a vibrant new an unlikely setting for a new arts centre, venue design of Stormen, which is actually cultural centre were sown in 1940 when a particularly one that has attracted two buildngs: Bibliotek and Kultuhus. German bombing raid left much of the town international attention for its quality and Bibliotek, with its library, reading rooms and in ruins. Reconstruction was necessarily versatility. performance spaces, is located on the hasty and inexpensive, with prefabricated waterside edge of the site, its huge windows lightweight housing and stone-clad Yet ‘Stormen’ – comprising a library, a affording the visitor a panoramic view across commercial buildings predominating. In theatre that converts into a concert hall, bars, the fjord. Kulturhus, abutting the town centre later years further public buildings were clubs, reading rooms and various on the inland side of the plot, has a 944-seat constructed on a grid system that has given performance spaces – has brought theatre/concert hall; a 250-seat multi- today’s town its current shape. unexpected fame to the small town of Bodø purpose drama and recital hall and a 400- in Norway. Influential London-based seat basement jazz and rock music club. This piecemeal post-war development, magazine The Architects’ Journal selected necessary to meet the needs of a population Stormen as its ‘Building of the Year’ for The buildings are designed to operate as a grown from 6,000 to more than 50,000 in 2014, while Christian Lindberg, Principal cultural hub, morning to evening. Bibliotek, little over 50 years, meant that by the 1990s Conductor of the Arctic Philharmonic with light cascading through waterside the local authority, Bodø Kommune faced a Orchestra, says Stormen’s concert hall is one windows, is the ideal place for study and conundrum: should it consolidate the grid or of the very best in the world. daytime events while Kulturhus is take a completely new approach to undoubtedly the busiest part of Stormen at regeneration? night. All the facilities in Kulturhus can be used simultaneously, if required.

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93780_Text.indd 15 22/05/2015 10:34 4.

A decade of debate ensued until, in 2008, a Arup’s appointment was across a Kulturhus, the performing arts building, decision was made: Bodø Kommune multidisciplinary portfolio comprising houses three venues and a full range of front- announced an international design acoustic and venue consulting; mechanical, of-house and backstage facilities: Lille Sal is competition for a waterside cultural quarter, electrical and structural engineering (to a 250-seat multi-purpose drama and recital offering entrants the choice of either concept design); and fire planning (during hall; Sinus is a 400-seat jazz and rock club; inner-city regeneration or consolidation. construction). The early days of the project and the undoubted centrepiece is Store Sal, a Many entrants plumped for regeneration but were focused on an intense period of design 944-seat theatre and orchestral concert hall. London-based DRDH took a very different development. Work on site started in 2011 approach, consolidating its design with the and was completed in November 2014. Designed to be a truly multi-functional existing town centre and locating the library space, with no compromise in acoustic or in a prime waterside position. The key elements of stormen operational standards for either theatrical or Within Bibliotek, the dominant volume is the orchestral performances, Store Sal is the Arup’s role reading room. This airy space houses an most complex of all the spaces within DRDH turned to Arup, both for help in array of shelves and study areas. In summer, Stormen. The restrained, elegant architecture developing their ideas to win the its floor-to-ceiling glazing offers visitors belies the deep collaboration required competition, then later to construct Stormen. inspirational views and glorious midnight between DRDH Architects and Arup to DRDH was attracted by Arup’s international sun. In winter, when daylight is at its make the space effective. capability, proven skill in concert hall design scarcest, it provides a welcoming public and expertise in spatial integration and gathering space against inclement weather. transformation. There was also a good Bibliotek also houses a community studio ‘cultural fit’ – Arup’s unique structure – a space for small lectures and where local 4. A bright and open stairwell accesses library and study rooms. accorded well with the DRDH ethos. aspiring artists can perform. Every detail is 5. Ballerinas from Bodø’s ballet meticulously designed: the performance school performed The Nutcracker in technology is carefully detailed to allow it to Store Sal, accompanied by the Arctic be hidden or removed, so the space can be Philharmonic Orchestra. used for art exhibitions (Fig 4). 6. A view of the town from The Green Bar in Kulturhus.

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93780_Text.indd 16 22/05/2015 10:34 Programming aspirations for the arts centre • Surfaces finishes and materials required were high, and simultaneous use of all review and dual design to achieve dual venues was planned which meant they had to functionality be in close proximity and available for Extensive and sophisticated variable concurrent use. With the city centre site absorption elements had to be deployed constrained on three sides by existing roads, plus the harbour to the north-west, achieving Spatial transformation systems would have the client’s spatial requirements and to change the venue’s geometry to reveal or architectural design was necessarily detailed hide acoustic finishes and specialist and compact. The proximity of high- technical systems as required. performance spaces combined with reduction of surrounding volumes led to The Arup Venues team is expert in multi- 5. complex structural, acoustic and functionality using spatial transformation operational challenges. technology. So the efficient design concept and competitive procurement strategy Changing brief subsequently devised meant the complex, The client’s aspirations further developed as novel moving shell system could be built for concept design progressed. Developments in similar cost to a traditional shell with an the regional music scene emerged that had acoustic enhancement system. significant implications for the design of Store Sal. Two local orchestras were The following sections outline the acoustic combined to form a new regional orchestra and technological concepts involved. – the Arctic Philharmonic – and the local annual music festival, already gaining in Acoustic transformation national importance, was expanded. The client required an audience capacity of about 1000. In orchestral mode, a It became apparent that the original reverberation time (RT) of about two competition requirement for a proscenium seconds is required for optimum theatre that could occasionally accommodate performance. For 1000-person capacity this an orchestra was only half the story. In equates to a room approximately 18m high reality, the client required a world-class and 18m wide. In theatre mode, however, concert hall which could act as a base for the such a volume is excessive – the ideal RT Arctic Philharmonic and a theatre of equal being closer to one second. quality. They needed an exceptional multi- functional venue capable of rapid conversion The desired reduction in RT was between concert hall and theatre. achieved by:

Scope change identified, rapid and Exposing absorption in the stage area 6. significant redesign was required. A and flytower traditional orchestra shell was neither Deploying variable acoustic drapes at The challenges practical – because space limitations technical balcony level Stormen’s engineering challenges sprang precluded its storage – nor suitable because partly from the technical and architectural it would fail to deliver sufficient acoustic Deploying a system of bespoke tracked aspirations of the design, partly from the performance. Electro-acoustic enhancement unity-absorbing sliding wall panels that nature of its environment. fell short of the client’s aspirations so a cover more than a third of the auditorium bespoke solution was required: the hall had side and rear wall areas. Availability and cost of materials was an to be physically transformed: issue. Bodø’s Arctic location meant that To prevent excessive low frequency shipping a suitable quantity of structural The ceiling of the auditorium needed to absorption, panel storage enclosures were steel was prohibitively expensive, while a be raised to create sufficient volume to carefully designed and lab-tested to ensure commercially-viable supply of ready-mixed achieve concert hall reverberance that in orchestral mode the absorptive panels concrete was available only due to the themselves were effectively isolated from • The stage flytower and wings had to the room. This was achieved by providing concurrent construction of a major new be closed off with suitably massive hospital in the city. Long periods of suitable mass and stiffness to the enclosures reflective surfaces to create a concert hall and by ensuring that all gaps into the sub-zero winter darkness added to the ‘shoe-box’ geometry construction challenge. enclosures are sealed when the panels are • A secondary suspended reflector array was retracted (Fig 12). The team also had to take into account required over the orchestra platform to control of aircraft noise – Bodø’s airport, achieve the early reflections necessary for only 1.5km away from Stormen, is a major performers to communicate clearly base for the Norwegian Air Force.

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93780_Text.indd 17 22/05/2015 10:34 Spatial transformation 1. Ceiling panels stored in flytower 5. Hinged ceiling panels folded down An array of innovative technologies enables 2. Hinged ceiling panels folded 6. Hinged proscenium panel down for storage Store Sal to be truly dual-purpose. As a 7. Auditorium acoustic panels deployed 3. Rolling lighting bridge 8. Side wall panels removed for theatre, its large stage, full-height flytower 4. Drapes and scenery flown stage access and variable-sized orchestra pit enable it to from above 9. Orchestra pit elevators host complex theatrical and televised shows 1 (Fig 7). When transformed to a traditional shoebox concert hall it can deliver world- class symphonic performances in a 3 critically-acclaimed acoustic (Fig 8).

As well as the acoustic and storage issues 2 4 5 associated with use of a conventional 7 orchestra-shell already noted, a particular problem is that as freestanding towers grow 6 in height, the base area and weight also expand. This makes tall towers very difficult 8 to store efficiently. For these reasons such a shell was both undesirable and impractical.

Instead, the orchestra is enclosed by a system of suspended movable wall and ceiling panels. The 14m-high wall panels move easily on an overhead track system 9 and store tightly against a side stage wall behind the theatre fly galleries. Acoustic 7. reflectors and motorised ceiling panels can be flown or folded into place above the stage and, together with the wall panels, these dramatically change the acoustics and 1. Hinged ceiling panels 6. Hinged proscenium panel aesthetics of the space. In theatre-mode a 2. Suspended ceiling panels 7. Auditorium acoustic panels retracted pair of the side wall panels hinge around to 3. Rolling lighting bridge 8. Tracked side wall panels form the sides of the proscenium arch with 4. Orchestral lighting bar 9. Orchestra pit elevators the top completed by folding down one of 5. Orchestral reflector array the ceiling panels.

Acoustic isolation To be acoustically effective, each 3 performance space must be free of noise 1 2 2 1 from building services, external sources or other venues in the complex. As a world-class concert hall Store Sal, must 6 achieve the particularly stringent background 4 5 7 noise level requirement of NR15, the industry standard for new concert halls. Extremely high levels of inter-venue 8 acoustic isolation are required to ensure these criteria can be maintained so that classical recitals can be held in Store Sal while pop music concerts are staged in Sinus directly below.

This has been achieved by constructing 9 Sinus and Lille Sal as independent isolated concrete boxes, mounted on elastomeric bearings, with no solid connections to the 8. rest of the building (Fig 9). The resulting level of isolation has been highly successful. 7. Store Sal in theatre mode. 8. Store Sal in concert hall mode.

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93780_Text.indd 18 22/05/2015 10:34 It is known to be greater than 90dB but has not been accurately measured because it’s not possible to safely generate a high enough sound level in one venue to measure the transmitted level in the other.

The result is a set of spaces that give the venue operators complete flexibility Stor Sal in which events can be scheduled at any time, without fear of disturbing adjacent performances.

Lille Sal Structure Sinus Isolated The ambitious use of such a compact structure building volume – with three independent Elastomeric bearings performance venues partially below ground – created significant structural design 9. challenges. Not only did the team need to 9. Section showing solve the coordination challenges typical for isolated structures. buildings of such technical complexity, but 10. Section detail showing the vertical stacking of primary and applied loads. acoustically-isolated structures meant 11. Structural model. developing creative solutions for load paths both during construction stages and in the

final configuration. Compression

A particular challenge was the requirement Applied loads Compression to position the primary rear support wall of Store Sal above the ceiling of Lille Sal in Internal stress Tension order to achieve the space planning which Reactions was fundamental to fitting the three venues into the building volume.

Lille Sal employed an inner concrete box independent from the primary supporting structure, so the scheme was developed such that the rear wall of Store Sal could span the full length of Little Sal, and then distribute the loads to other walls in the opposite plane. 10. However, it was essential that the propping required to support the weight of the formwork and wet concrete of the wall in the temporary condition could not penetrate the completed ceiling of Lille Sal. The concept therefore integrated a system of precast beams that could provide support in the temporary condition while retaining a compact and efficient framing arrangement in the final configuration (Fig 10).

The Arctic Circle premium on structural steelwork meant steel was only used where absolutely required for cantilevering balconies and flytower grid. The generally preferred structural framing solution was precast concrete which was used where possible, though achieving the ambitious and 11. highly integrated layouts meant the majority of the structure was cast in-situ (Fig 11).

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93780_Text.indd 19 22/05/2015 10:35 12.

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93780_Text.indd 20 22/05/2015 10:35 Seating and sightlines To minimise acoustic shift, seats were Theatre use requires a deep fixed stage area. specified to provide a very similar amount of For dramatic performances, the audience absorption when occupied or unoccupied. needs to be relatively close to the stage to These are tip-up seats with absorbent see performers’ facial expressions. undersides which only see the room acoustic when they are unoccupied. Laboratory In orchestral use, a large area of rear wall is testing was done prior to installation to required for effective envelopment confirm the seating performance. reflections. In addition, balcony overhangs need to be minimal and high to ensure that Ceiling and balcony-fronts all seats enjoy the reverberant field. Having established the acoustic and theatrical concept for the room, various As a result, the optimum rake required for elements of detailed design were undertaken 15.

the stalls seating needed to be as shallow as to optimise the room’s performance. 15° possible without compromising sightlines, while balconies above were more steeply Parametric genetic genome optimisation 8° raked (Figs 13–14). processes in Grasshopper and Galapagos 0° were used to optimise the profiles of the The Arup team carried out detailed design ceiling and balcony-fronts to ensure even optimisation of sightlines, followed by coverage of early energy to the two balcony visualisation studies (using Microstation levels. The geometric optimisation was 8° and Rhino) throughout the hall to give performed using three on-stage source 0° confidence that the acoustic and visual positions (downstage, mid-stage and 10° requirements were satisfied. upstage).

Changes in hall occupancy can lead to Ceiling and balcony soffit panels were changes in reverberance due to differences in designed to scatter sound from the stage in the absorption between occupied and order to prevent strong specular reflections unoccupied seats. If not carefully managed, or image shifting, and to provide every seat this phenomenon can give rise to an acoustic with early reflection energy with a range of shift between an unoccupied orchestral time delays and from a range of locations. 16. rehearsal and a sold-out performance. An acoustic that doesn’t change between these Using similar techniques, side balcony- two states gives artistes confidence that what fronts were optimised both to maximise they experience when they rehearse is what sound reflections from stage towards the they will hear when they perform. audience on the first and second rear balconies and to ensure even coverage with no ‘hot spots’. The initial balcony-front design was a vertical profile, the optimisation routine changed the surface calculating the optimum warp/twist to be applied to the surface (Figs 15–17).

The optimisation performed in Grasshopper 17. is based purely on ray-tracing to calculate the specular reflections of incident sound 12. Stor Sal with auditorium paths – but sound is not always specularly acoustic panels revealed. reflected. Reaction to incidence on a surface 13. Sightline visualisation from depends on a number of factors including the the balcony. 13. surface finish, geometry and panel size. 14. Sightline visualisation from So, in order to check the resultant acoustic the stalls. parameters, the results from the geometric 15. Initial balcony-front ray-tracing optimisation were also analysed reflection coverage. with Odeon to take into account scattering 16. Optimised balcony-front and diffraction (Fig 18 overleaf). To achieve warped/twisted profile. the precision-engineered surfaces resulting 17. Optimised balcony-front from the optimisation exercise, the ceiling reflection coverage. and balcony-fronts were constructed from calcium sulphate panels. These were chosen both for the high density of the material and its ability to be accurately machined. 14.

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93780_Text.indd 21 22/05/2015 10:35 18. Optimised predicted performance using Odeon. 19. Motorised movable lighting bridge. 20. A colourful and welcoming play area for younger visitors to the library.

T30 at 1kHz Overhead ensemble reflectors are typically > = 2.60 suspended above the orchestra, usually at 2.44 about 8m above the platform to provide a 2.28 2.12 reflecting surface. In Store Sal, they are 1.88 suspended through slots in the ceiling 1.72 panels. The array was adjusted in 1.56 collaboration with the orchestra to optimise 1.40 the sound on the platform and assist in 1.24 providing a beautiful string tone in the 18. 1.08 0.92 auditorium. 0.76 < = 0.64 Auditorium walls To assist with room acoustic control, bespoke tracked timber panels in the auditorium walls reveal semi-rigid glass wool panels behind acoustically transparent fabric. These materials are used because their full bandwidth acoustic absorption Rolling bridge in parked position properties are more tonally effective than soft drapes or banners. Various areas of the wall panels can be exposed to suit the Limit of travel performance and programme type. 19. Lighting bridge Staged performance work requires front-of- house lighting. Luminaires require access for rigging, focusing and maintenance but in orchestral mode traditional theatre lighting bridges at high level are acoustically undesirable because they reduce the volume, add to the absorption in the space and block useful reflections from the ceiling. They Orchestral reflector array The design of the reflector array is a obscure optimised ceiling finishes, also, and Orchestral ensemble reflectors are essential complex matter. Five main design criteria can detract from the architectural concept. platform elements in concert halls where the need to be addressed. These are: platform-to-ceiling height is significant and To resolve this conundrum, Arup developed the orchestra is large. Once the height of the • Number of reflector panels an innovative motorised moving bridge, stage exceeds 12m and the width of the stage • Location of reflector panels relative to similar to an industrial gantry crane. This is more than about 15m, the useful the platform spanning access walkway is designed to roll reflections from the stage walls and ceiling from front to back of auditorium to enable are reduced in power, affecting the ability • Size of each reflector panel rigging and focussing of lights hung on the of players to hear themselves and other • Curvature of the reflector panels fixed overhead bars, access to strong points sections of the orchestra. The suspended in the ceiling and provide lighting positions reflector array provides those reflections, • Height of the reflector array over for theatre use (Fig 19). assisting the musicians with their timing, the platform. tuning and ensemble. The bridge is accessed by technical staff via Two acoustic design elements are assessed. a number of safety interlocked gates, spaced Ensemble reflectors also provide some high These are the ‘cut-off’ frequency, determined out along the galleries high above both sides frequency early reflections to the audience, by the size of the panels and their height (the of the auditorium. The bridge is finished especially from the string section. greater the cut-off frequency, the better) and with architectural panelling on the audience the coverage of the reflected sound on the side and disappears when ‘parked’ above the platform. proscenium for orchestral concerts, leaving the ceiling completely unimpeded.

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93780_Text.indd 22 22/05/2015 10:35 Side-wall, proscenium and ceiling panels Tracking side-wall panels (14m high) move from their parked position to one side of the stage and complete the side-wall enclosure to the orchestral platform. These are sufficiently massive, stiff and diffusing to provide adequate ensemble reflections to the performers and are shaped to project sound into the auditorium. To make the system simple to use and avoid the need for motorisation (thus reducing maintenance and complexity) they are hung from low friction steel wheels and may be hand-rolled (by one person) into their parking position.

The proscenium is formed by large vertical and horizontally hinged panels. The proscenium header hinges upwards into a horizontal position covering the front part of the flytower. The side panels (10m high) hinge through 90° forming the front part of the orchestra enclosure when stored.

Three more ceiling panels are used to visually and acoustically close off the flytower: two rotate and are stored vertically in the flytower, while the upstage panel is hinged so that it hangs down against the back wall. 20.

The back wall itself is timber clad to match References Structural Engineer (Detailed design and construction): the side walls and ceiling panels, and is the (1) OLCAYTO, R. (2015) Building study: Norconsult AS, Bodø Services Engineer (Detailed only fixed element on the platform. Although Stormen Concert Hall and Library, Bodø, Norway. design and construction): Norconsult AS, Bodø unintended during design, this surface has Architects Journal. Acoustic Consultant (Local collaborator): Brekke Strand, Oslo Façade Engineer: Ramboll Façades Ltd, also proved very effective for projection of Authors London Fire Consultant: Norconsult AS, Bodø scenic video during concerts despite its James Beer is a Consultant with the Acoustics and Lighting Consultant: Norconsult AS, Oslo uneven, oak veneered finish. Venues team in the Winchester office. He was responsible for the project managing the venue technical Image credits Conclusion systems during construction and was involved in the 1–4, 12, 20 DRDH Architects / David Grandorge; design of the sound and communications systems. 5, 9 Nigel Whale; 6 Arup / George Ellerington, Arup’s unique multidisciplinary skills Matt Atwood is a Senior Consultant in the Venues team 10–18 Arup; 7, 8, 19 DRDH Architects alongside DRDH’s excellent design vision in the Winchester office. and careful site supervision added up to an William Algaard is an Associate Director in the London effective partnership which delivered a office. He led the structural and building services flexible, elegant, efficient building – a good concept design. example of Ove Arup’s vision of total George Ellerington is an Associate in the Winchester architecture in action office. He was responsible for the concept and detailed design of the Store Sal shell system and for technical Rory Olcayto, writing in the January 2015 planning of the performance spaces. edition of The Architects’ Journal delivered Ian Knowles is a Director of the Acoustics and Venues team in London. He led the multi-disciplinary design of an emotional verdict: the project from competition to completion.

“Strange as it may sound, Stormen’s Project credits off-white concrete walls and columns, its Client: Bodø Kommune Architect: DRDH Architects, room-like staircases and lofty reading rooms, London Acoustics, Venues, SMEP Engineer, Fire Consultant (review) – Arup: William Algaard, its cosy bars and basement clubs, and its James Beer, Craig Bowden, Richard Bunn, regal theatre-cum-concert hall, all David Connery, Ned Crowe, Luca Dellatorre, painstakingly-calibrated, all exquisitely Ed Elbourne, George Ellerington, Philip Hives, constructed, exude a kind of intelligence. Ray Houghton, Matthew King, Ian Knowles, Ian Pegrum, Anna Piasecka, David Ripley, Poetry is useful here, so let’s reach: like Luke Robertson, Alessio Rocco, Stephen Secules, Byron’s high mountains; Stormen is a Alex Wardle, Sam Wise Project Management: feeling. And that feeling is Bodø itself. Ramboll Norge, Trondheim Stormen is the feeling of a town.”

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93780_Text.indd 23 22/05/2015 10:35 1. Singapore Sports Hub

Authors Andrew Henry Chia Wah Kam Clive Lewis Malcolm Smith Mike King Nick Boulter Peter Hoad Ruth Wong Scott Munro See Lin Ming

1. Singapore Sports Hub, opening night, June 2014. 2. Stadium design conceptual sketch. 2.

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93780_Text.indd 24 22/05/2015 10:35 Introduction expressways, local pedestrian networks and This article focuses on how the architecture Singapore celebrated the opening of Asia’s the island-wide park connector system to and engineering for the National Stadium first integrated sports, leisure, entertainment surrounding residential areas. was defined. It provides an overview of the and lifestyle destination – the Singapore inputs that shaped the design of the wider Sports Hub – in June 2014. Located on a At the heart of the Sports Hub lies the new precinct – from the original masterplan 35 hectare waterfront site, within easy reach National Stadium conceived as a unifying design to specialist engineering concepts of the city centre and international airport, protective canopy that connects all parts of developed for integrated energy the Sports Hub is key to the Government of the Sports Hub master plan. The dome to infrastructure, environmental and Singapore’s urban development plan and the stadium has a span of more than 310m, microclimate design, acoustics, fire central to its 2020 vision for a sustainable, making it the largest free-spanning dome engineering, pedestrian modelling, blast healthy and expanding population. structure in the world – an awe inspiring resilience, sports and feature lighting design. event space. Air-cooled, and designed with a The design of the precinct capitalises on movable roof and retractable seating for a its location. It is well connected and wide range of sport and leisure events, it is inclusive thanks to easy accessibility from a state-of-the-art stadium. the Mass Rapid Transit network, adjacent

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93780_Text.indd 25 22/05/2015 10:35 The background 3. The former Kallang National Success in delivering the project was truly In 2001, the Singapore Government Stadium. the result of global collaboration with published a paper recommending 4. Designed to orientate towards the Dragages, Arup, DP Architects and AECOM redevelopment of the existing National CBD, the National Stadium is in constant dialogue with the city. working together as a team. Expertise in Stadium at Kallang Bay into a multi-use sports design, architecture, masterplanning, 5. The waterfront, tree canopy and sports hub. A feasibility study was shaded walkways are key elements structural and environmental design enabled commissioned to look into the type and size of the scheme. the team to put forward place-sensitive and of facilities to build, taking into often ground-breaking ideas. consideration local community requirements and the potential for international events. The site Arup’s urban design team recognised the A commercial model was developed to potential of the old Kallang sports stadium, ensure all facilities would be fully utilised; a on its prime waterside site, to make the public-private partnership (PPP) was Sports Hub a feature of Singapore’s famous established to take responsibility for event skyline. planning in addition to building, operating and maintaining the Sports Hub for its first The silhouette of the city, and the connection 25 years; and a design competition was between stadium and city, were essential organised. keys to the form and layout of the masterplan. Dragages Singapore Pte Ltd, part of the 3. French company, Bouygues Construction, Local stories which influenced the team formed a team with Arup and DP Architects. included that of the Kallang Roar: the sound The team offered the mix of local knowledge of the 50,000 strong crowd in the old and international experience needed to meet stadium that could be heard across Kallang the complex requirements of the brief and Basin, in the city itself. the consortium was successful, being selected as winner of the competition, from a These considerations all contributed to shortlist of three, in January 2008. shaping both the masterplan and the form and orientation of the stadium which is a Following further changes to the brief, horseshoe-shaped bowl, within an open- AECOM joined the team as the project went ended roof form, rotated to focus on the into detailed design phase. heart of the city. 4. Arup’s role 5. During the competition phase, Arup’s sport and urban design teams in London, led by Glen Plumbridge and Malcolm Smith, integrated work from offices in Manchester, Singapore, Sydney and Melbourne with input from specialist designers in London, America and Australasia.

At detailed design stage, 70 architects and engineers were working on the project. By project-end more than 600 Arup employees had been involved, with approximately 80 relocating to Singapore to assist in the delivery effort.

The post-competition and delivery phases were led by Andrew Henry (Project Manager), Mike King (Structures Lead) and Clive Lewis (Architecture Lead).

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93780_Text.indd 26 22/05/2015 10:35 2

3

1 9

7

6 1. National Stadium 2. OCBC Aquatic Centre 8 3. OCBC Arena 4. Singapore Indoor Stadium 5. Water Sports Centre 5 6. Kallang Wave Mall 4 7. Offices 8. Singapore Sports Museum 9. Splash-N-Surf

6.

The masterplan 1. Primary iconic structures – the National In addition to urban design work, the team Stadium and the existing Singapore had to develop solutions to deal with poor Indoor Stadium building ground conditions. The site comprised 2. Secondary structures – the aquatic centre reclaimed land (it was originally developed and the multi-purpose indoor arenas with as Singapore’s aerodrome in 1935) which their characteristic roof forms which abut meant an elevated stadium concourse was the stadium’s unifying plinth level required to avoid building large areas of basement. 3. Plinth – comprises a circle of two-storey buildings around the stadium perimeter. 7. This requirement led to a breakthrough in The roof-level of the buildings aligns with the masterplan: an elevated stadium created the Sports Promenade. 6. Overview of key facilities within a natural two-storey plinth into which all The architectural team was passionate about the Sports Hub. other facilities could be integrated. The how the stadium related to its surroundings, 7. Early sketches determining the result enabled efficiency in site planning that the intention being to attract public interest distinct silhouette of the Sports allowed for large plaza areas, waterfront and drive participation in the wide range of Hub – the dome structure of the National Stadium complementing promenades and landscaping around sports facilities on offer. In order to achieve the precinct. the inverted peaked roof of the this, they introduced pedestrian routes across Singapore Indoor Stadium. the site to connect key elements, such as the To organise the core elements in the brief metro and the waterfront, via a mixture of – the new stadium, the existing Singapore tree canopy and shaded walkways. Routes Indoor Stadium, the new aquatic centre, two around the perimeter of the stadium itself multi-purpose indoor arenas, retail and office were developed into what is now the space – the team defined an architectural 100Plus Sports Promenade. hierarchy comprising three typologies:

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93780_Text.indd 27 22/05/2015 10:35 8.

9.

National Stadium architectural design In terms of location, the dome structure The event programme was also an important The decision to develop the iconic dome complemented the existing Kenzo Tange’s consideration. The dome form would envelope to the stadium was driven by the Singapore Indoor Stadium (SIS). reinforce the acoustic energy of the crowd local climate, the site location and the for sports events and create a dramatic proposed event programme. Renders of the two buildings silhouetted setting for concerts, providing a vast above the water line convinced the team they projection surface for interactive sound and The tropical climate required a unique had generated one of Singapore’s most light displays. The open-ended design would architectural response because visitors impressive skylines – the simple dome form provide breathtaking views out across the needed protection from sun and rain, both of the new National Stadium juxtaposed city and provide all types of events with the inside and outside the stadium. A dome was against the inverted curve ‘peaked’ roof of skyline of Singapore as their backdrop. structurally the most efficient form to the SIS building. achieve the extended spans required to cover this area. The brief asked for a retractable The architecture was designed to roof to shade spectators during events, and complement the SIS building – the silver 8. The stadium roof opened to early calculations indicated that less steel reflective metal roof and steel exoskeleton, the sky. would be required to support the moving the neutral tones of the concrete base, and 9. The stadium roof in its closed roof using a dome rather than a cantilever the lush green plinth, with facilities such as position. roof structure. restaurants integrated, were all key elements. 10. The impressive city skyline visible from the open end of the stadium.

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93780_Text.indd 28 22/05/2015 10:35 10.

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93780_Text.indd 29 22/05/2015 10:35 11.

Integrating the bowl and roof football or athletics viewing. In Singapore, The new stadium is the only one in the world however, the seating bowl needed to achieve custom-designed to host football, rugby, the best balance for both athletics and cricket and athletics. Arup’s challenge was to football viewing. design a 55,000-seat stadium bowl for optimised viewing of these sports while To achieve this, the Arup sports venue minimising the footprint of the roof dome. design team developed a section profile which located close to 30,000 seats within The brief required the lower-tier bowl to be the retractable lower tier bowl, with 12. retractable and for spectators in all tiers to sightlines developed to allow these seats to benefit from an energy-efficient cooling move 12.7m closer to the football pitch. system. The development of the cross section to the seating bowl was critical to Using parametric bowl generation software maximise the benefit of introducing a to complete optimisation studies, the team moving tier system. arrived at a 3D form for the bowl and simultaneously studied the impact of In 2006/7 there were only two stadia in the reducing the geometry to the stadium roof. world with retractable seating and a The final design for the bowl enabled the permanent athletics track – Stade de France long span at the dome to be reduced to in Paris and Oita Stadium in Japan – and 310m. However, at this diameter, it was both of these stadium were biased to either still the largest free-spanning dome structure in the world.

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93780_Text.indd 30 22/05/2015 10:35 11. Roof structure as an integral part of the stadium’s architecture. 12. Sydney Opera House would sit comfortably inside the stadium. 13. Digital Projects – 3D model for architecture development of the roof. 14. Architectural visualisation of the roof structure.

Roof architecture and structure The dome roof form was chosen as it is inherently a highly structurally efficient geometry for a roof structure of this scale, especially one that integrates a retractable roof. Singapore is a unique location – no significant seismic activity, low wind and, of course, no snow load – so it presented the Arup team with a unique architectural and structural opportunity.

The initial target was to reduce steel weight by leveraging the inherent efficiencies of the shell roof form. One outcome of this was reduction in the depth of the primary 13. structure as it came to ground. Two control surfaces were established to define this – a sphere to the top and a torus to the bottom surface – with the roof structure reducing from a maximum depth of 5m to the centre of the dome to 2.5m at the base. This optimised structural solution provided an architectural benefit at ground level by reducing the proportions of the structure to something more in keeping with the human scale.

Reducing dead load wherever possible was a key goal and the team estimated that for every 10kg of weight added to any part of the shell structure, a further 4kg would need to be added to hold it up. This was a strong influence in the design of the moving roof structure, as well as the moving / fixed roof cladding design. The result is a dome which 14. uses one third of the steel weight per square metre compared to other large-span structures of this scale.

The team wanted to simplify the detailing of all complex node intersections across the entire roof and develop a standardised family of node details that could be replicated wherever possible. This required an update to the geometry of the roof to achieve a more symmetrical design than the competition- winning roof geometry. An additional parallel truss was added, the main gutter trusses were realigned, the geometry of the roof opening was adjusted and the diagonal trusses simplified.

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93780_Text.indd 31 22/05/2015 10:35 15.

16. 17.

15. The moving roof, constructed Moving roof cladding fixed roof to be reflected in the moving roof from translucent multi-layered ETFE A lightweight cladding system was required geometry. However issues related to pillows, can be illuminated at night. for the moving roof to provide shade to the structural movement and water ponding soon 16. Mock-up of the movable roof. seating bowl and reduced solar heat dictated a different design solution. 17. The roof is made of multi-layer gainwhile at the same time offering ETFE pillows and embedded with translucency so that the event space could The flexibility of the moving roof structure LEDs, turning it into a large digital screen. be naturally lit during the day. required a design with sliding bearings so it became important to avoid small pillow A multi-layer ETFE pillow was chosen modules because intersections between to meet these design requirements and at extrusions would need to be a fixed joint the same time provide the opportunity to (something that would not work illuminate the moving roof at night. Sized at structurally). Also, as an actively inflated 20,000m2 the moving roof is one of the roofing system, it carried the risk of pillows largest addressable LED screens in the deflating (either through puncturing or pump world and an unmistakable feature on failure) so water ponding was a serious Singapore’s skyline. design concern. The decision was taken to change the pillow format to long extruded The team worked closely with the appointed pillows that ran parallel to the short edge of subcontractor (Vector Foiltec) to achieve the the moving roof. In this way, water would best visual arrangement of pillows. The not be retained to the moving roof area, and original intent was for the patterning of the junctions between extrusions could be minimised.

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93780_Text.indd 32 22/05/2015 10:35 Fixed roof cladding The architectural treatment of the fixed roof cladding expresses the design and geometry of the structure, while meeting environmental performance requirements to ensure spectator comfort within the stadium.

The main areas of the roof dome are clad in a profiled aluminium rain screen cladding system, while the structure is expressed using a recessed smooth panelised cladding system. The team worked with the appointed subcontractor (Craft) to develop an integrated cladding solution that met the design intent architecturally, achieved the weight constraints structurally, met technical requirements related to acoustics, provided thermal insulation and enabled access for maintenance.

The result was a ‘super lightweight’ cladding construction that weighed less than 30kg/m2 (a significant reduction when compared to a standard standing-seam construction that 18. would typically weigh 60kg/m2 or more for the same technical performance). This was achieved through the design of a ‘unitised’ cladding system that had a number of significant advantages for the roof envelope:

• The soffit lining could be adapted to be either perforated or solid to achieve the acoustic requirements for the stadium (achieving the same performance with a trapezoidal deck would have been a major challenge) The cladding system could be built on the ground, to improve accuracy and tolerances, and lifted into position using 19. the same cranes that constructed the roof steelwork The number of construction workers required on the roof at any one time was reduced – a health and safety benefit, as well as a reduction in construction programme time and cost.

A unique part of the architecture of the NST 18. Detail of cladding systems – dome is the visible expression of the between fixed roof and giant louvres over the Sports Promenade. structural geometry within the roof cladding. 19. Detail of fixed roof cladding Recessed scupper areas were aligned to system. the primary structure, with the cladding to 20. Architectural rendering showing these zones continuing through the Sports movable roof and ETFE pillows, Promenade to complete the visual expression fixed roof aluminum standing seam of the roof structure to the support location cladding and giant louvres PTFE at ring beam level. The diagonal ‘scupper’ fabric cladding. zones are integrated into the night time illumination of the roof with LED node lighting. 20.

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93780_Text.indd 33 22/05/2015 10:35 21.

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93780_Text.indd 34 22/05/2015 10:35 21. Giant louvres providing shade and shelter to the Sports Promenade. 22. Rendering of Sports Promenade looking towards the hospitality space. 23. Early rendering of Sports Promenade with greenery integrated.

22.

Sports Promenade The giant louvres provide natural ventilation and protection from sun and rain for the Sports Promenade. Clad in PTFE fabric, the louvres align to floor levels within the stadium enabling views to the outside.

For rain protection, the design needed a 30 degree overlap between each louvre. Arup used optimisation software to achieve the best fit within these constraints while minimising the physical area of louvre fabric. The giant louvres are an integral part of the building physics design as they shade internal glazed façades and allow natural ventilation into the stadium bowl – a key part of the low-energy bowl cooling strategy.

Internal façades The internal façades and slab edges are the visible external face of the stadium within the Sports Promenade, so they are important 23. in the architectural language of the building.

The internal façades organise entry locations at Level 3 of the stadium, provide break-out zones and viewing decks to the premium The internal façade is defined by three-arc These were organised into five main façade concourses at Levels 4 and 5, provide geometry that simplifies the elliptical form zones – premium entrance plus glazed open-sided concourse areas for general of the façade in plan. As the façade is restaurant, upper tier escalator access, lower spectators at Levels 4 and 6 and provide two inclined, this was an important design tier access plus break out balconies, open- large glazed restaurants to the centre of the decision because it allowed all façade sided concourse plus sky terrace and solid north and south façades. elements to be defined as part of the surface core zones. of a cone rather than a more complex This space defines the ‘tropical stadium’ two-way curved geometry. This created a legible façade specifically concept, introducing lush green landscape designed to assist with wayfinding and through the design of sky terraces and With this simplified geometry set up, the orientation for spectators arriving at the planters to slab edges. A continuous planter internal façades were developed to conform stadium within the Sports Promenade. runs to the edge of the Level 4 slab and to a set of glazing, balustrading and planters connects with a vertical planter screen. typologies which could be repeated around the 800m façade to the stadium.

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93780_Text.indd 35 22/05/2015 10:35 24. This drawing of the stadium shows how the facilities on each level stack up, coming together to form a coherent whole.

Level 6 Internal layouts Level 1 – players village; venue operations; plant This is the main ‘back of house’ zone within the building, with the players’ village to the north, venue operations and storage facilities, catering facilities, refuse areas, and plant all accessed from a wide service access road. At level 1, adjacent buildings occupy Level 5 the zone within the ring beam and outside the service access road, with the indoor arena, office, retail and aquatic centre integrated into the footprint of the dome.

24. Level 2 – VIP entry; media; offices; plant This level provides additional plant space, offices for the consortium management team, work areas for media, a secure VIP entry to the north of the stadium, parking for 50 cars Level 4 and access to a dedicated lift to the VIP suite at level 5.

Level 3 – main entrance level Level 3 is the entry level for all ticket holders. Access to entry locations is via the Roof open Sports Promenade which provides a covered pedestrian route to all facilities within the precinct. Level 3 is also the lower tier concourse level.

Level 4 – premium concourse Level 3 Provides up to 3,000 premium ticket holders with access to two main restaurants, four extended concourse zones, break-out balcony areas and landscaped roof terraces to the open end of the stadium.

Roof closed Level 5 – premium suites With 62 suites ranging in capacity from 10 – 30 persons, and a VIP suite for 60, this level is served from a central elevator access with balcony views over double-height Level 2 restaurants to the north and south stands, and breakout balconies with views into the Sports Promenade.

Level 6 – upper tier concourse Catering for 12,000 general spectators, the upper tier concourse is designed as an open-sided floor plate, with panoramic views through the louvres to the precinct around the stadium and the city beyond.

Level 1

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93780_Text.indd 36 22/05/2015 10:35 25.

Structural design Additional software was written to extract Digital Projects A specialist team within Arup was tasked further design information from the analysis with developing bespoke software to manage model (such as connection design forces and inputs from the various design software used fatigue stress concentration factors) and in the design process (the latest BIM embed them within the Tekla model. This modelling software was essential to the process allowed the BIM model to be issued integrated architectural design and to the steel contractor containing all the engineering of the Sports Hub, particularly information necessary to deliver the roof’s the stadium roof). complex structure.

The design team wanted a feedback loop so The parametric model was used to control a that one software could inform another of multitude of other relationships between defined positions, co-ordinates and elements which it would have been Oasys GSA dimensions for the roof elements. impossible to achieve using conventional A parametric model was built in Digital software. Each parameter was treated in the Projects (DP) allowing the roof structure to same way – structural and architectural be quickly assessed structurally and requirements were considered, an optimised redefined as the design developed. parameter agreed and inserted into the geometric control model for the roof. The parametric DP model was linked to In time, a fully editable 3D model of the Arup’s structural analysis software General stadium roof was completed which defined Structural Analysis (GSA) via bespoke every constraint imposed on the roof and in-house software allowing optimisation of could be used independently by every the roof’s form via varying truss depths, member of the team. layout, arch rise and other parameters that define its geometry. The efficiency of this Stadium roof structure process was key to be able to iterate through The 310m-span roof rises to a height of Tekla numerous design solutions during design approximately 85m from pitch level (76m development. from the elevated post-tensioned concrete ring beam). Comprising a fixed roof and two Once imported into GSA, the structure was movable roof components, the structure optimised using in-house software, totals approximately 7,400 tonnes of developed specifically for the project, that structural steel plus connections. employed an interactive approach based on 26. ‘fully stressed design’. Then, with the structural sizing optimisation complete, the 25. National Stadium under structural analysis model was converted into construction in December 2013. a Tekla Structures BIM model from which 26. Feedback loop established for all the construction drawings were produced. information transfer between architecture, engineering and construction models.

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93780_Text.indd 37 22/05/2015 10:35 27.

The fixed roof spans clear across the stadium Two transverse trusses that are parallel to compression to support the movable roof as with no support taken from the stadium the pitch and form the long edges of the the roof closes. The ring beam and ring beam seating ‘bowl’ concrete superstructure. The roof opening support column pairs restrain the thrust fixed roof also directly supports the movable Diagonal trusses linking corners of the forces generated as the steel roof tries to roof via a series of ‘bogies’ running on the rectangular forms described by the spread, and transfer vertical forces at each of parallel ‘runway trusses’ that span transverse and runway trusses the roof nodes to the columns below. Vertical perpendicular to the pitch axis. The forces are then carried by the columns into structural dome form of the roof imparts • Interceptor trusses which define the the bored pile foundations. large tensile forces into a post-tensioned junction between the fixed roof cladding, concrete ring beam, built approximately 9m supported on the secondary trusses above; The secondary trusses are 3D triangular from ground level, which acts to restrain the and the giant louvres, clad in PTFE fabric, trusses but span in one direction only and roof from spreading. below. match the depth of the primary trusses at each location where they meet. The trusses A fundamental principle in the design of the The primary trusses form the principal steel are formed using CHS of maximum chord fixed and movable roofs has been to create a load carrying members in the roof. They size 356mm diameter and are faceted at all very stiff fixed roof and a flexible movable vary in both depth and width with a truss node points to match the spherical roof structure to minimise the tendency of minimum depth of approximately 2.5m at geometry of the roof. Both top and bottom the movable roof to rack or skew and jam the base nodes and a maximum depth of chords of the secondary trusses connect into during operation. approximately 5m at the centre of the dome. the primary trusses. All trusses are 3D triangular trusses Fixed roof structure fabricated from circular hollow sections The giant louvres that enclose the Sports All loads on the roof structure are (CHS) with chords sizes of 457mm diameter Promenade are made up of trusses in transmitted to the concrete ring beam by a and 508mm diameter. horizontal planes spanning between the network of triangular-formed primary trusses diagonal and parallel runway trusses as well creating a very stiff 3D shell or dome There is an opening in the roof, as trusses in vertical planes suspended from structure. approximately 220m long and 82m wide, the interceptor trusses. All trusses are formed over the football pitch. The shell action of from CHS sections. The connections These primary trusses comprise: the fixed roof is affected by the opening in between the louvre framing and primary the roof, where point loads from the bogies Six parallel runway trusses spanning across trusses are detailed to ensure that the louvres on the runway trusses result in additional the stadium, perpendicular to the pitch axis do not form part of the global roof framing bending in those trusses. Across the opening, system and only exert load on it, rather than the primary trusses act in bending and attract load from it.

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93780_Text.indd 38 22/05/2015 10:35 Transverse trusses Runway Runway trusses trusses (five total) over roof opening

27. Sports Promenade – public access area around the stadium. 28. Fixed roof primary trusses and ring beam. Ring Diagonal beam trusses Runway trusses 29. Fixed roof secondary trusses (five total) over roof opening 30. There is an opening in the roof, Interceptor truss approximately 220m long and 28. 29. 82m wide.

30.

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93780_Text.indd 39 22/05/2015 10:35 Movable roof structure Similar to the fixed roof, the movable roof is made up of 3D triangular trusses which span approximately 48m between the runway trusses.

There are four spans of movable roof trusses between the five supporting runway trusses.

The movable roof framing has been developed to minimise interaction between the movable and fixed roof structures. This is achieved by introducing physical pin connections at the purlin or link members between the parallel trusses forming the movable roof as well as lateral sliding bearings between the movable roof and its supporting bogies. The end detail where the trusses are supported on the bogies is also pinned at one end to avoid continuity of the 31. trusses over these runway truss supports.

The articulation of connections, as well as the use of bearings, is intended to allow the 32. movable roof, to follow the fixed roof displacements without introducing large Bogie supports stresses in the structure or significant horizontal loading at the support points.

The cladding of the movable roof is a lightweight ETFE inflated pillow system, with the pillows supported on ‘T’ brackets welded directly to the top CHS of the moving roof structure. The ETFE system has

Runway truss line been designed to allow for a considerable amount of movement with PTFE sliding bearing integrated into the design. ‘Purlins’ between Top surface of truss trusses pin-ended to brace in plane allow in-plane

Moving roof Runway truss line Main features Operates whilst the stadium is in use Operates in moderate rain Pin-ended to allow flexibility Closing time 20 minutes Condition 3 Bogies 20 bogies per panel, five braked (one per arched truss)

Mechanisation 16 winches (8 per panel, located in clusters of details four on two arched trusses) Bogies supporting movable Power and control signal transfer via energy roof running on runway beams ‘drag link’ chain Movement Control system is operated from main control Runway trusses monitoring room using purpose-written software. Roof position tracking and synchronisation is achieved by an encoded rail track monitoring bogie positions. Absolute linear encoders mounted on bogies allow the roof movement to be controlled to within millimetres. For redundancy and safety, a secondary encoded 31. The movable roof lighting head is mounted side by side to the primary forms the largest addressable LED position and counter checking position. screen in the world. This ‘anti-skewing’ system ensured at any time a maximum skewing position difference of 32. Movable roof truss detail. 35mm between any of the 5 trusses.

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93780_Text.indd 40 22/05/2015 10:35 Movable roof systems During the competition phase of the project, Arup developed designs for the moving roof mechanism based on a range of drive options. The geometry of the dome roof and the desire to reduce steel weight led to selection of a cable drive mechanism, a significant benefit being that it allowed for less stringent control on the deflection criteria between the fixed and moving roofs. This in turn allowed for efficiencies in roof steel weight.

The moving roof is unique in that it is asymmetric in plan and maintains an open end. To minimise structural depth and weight, cross pitch runway trusses supporting the moving roof tracks were inserted. The preliminary design was completed with a movable roof comprising a 33. 3m structural depth and a cable driven system that linked to winches located inside the stadium. This solution minimised the Original schematic design of the cable route and winch location for amount of equipment required on the roof movable roof drive system and followed similar proven schemes such the one at the Oita Stadium, Japan.

Further refinement, later in the design process, included relocating the winches onto the moving roof structure itself. This removed the need for cables to return into the lower levels of the stadium, simplifying the internal planning of stadium and avoiding the need to protect spectators from the possibility of cable failure. It also prevented large forces being imposed on the fixed roof at each cable drop location 34. reducing steel weights to the long span structure to the fixed roof.

Revised self-contained winch and Roof position tracking and synchronisation cable system within the movable is achieved by an encoded rail track roof leading to significant increased efficiencies monitoring bogie positions. Absolute linear encoders mounted on bogies allow the roof movement to be controlled to within millimetres. For redundancy and safety, a secondary encoded head is mounted side by side to the primary position and counter checking position.

This ‘anti-skewing’ system ensured at any time a maximum skewing position difference of 35mm between any of the 5 trusses.

35. 33. Snapshot of 3D model illustrating Arup’s reference design for movable roof transportation system. 34. Original design for movable roof drive system. 35. Revised design for movable roof drive system.

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93780_Text.indd 41 22/05/2015 10:35 Fixed roof connections A number of different connection types were investigated for the complex geometry of the tube-to-tube connections of the fixed roof. Three key factors were assessed when selecting the connection detail: fatigue sensitivity (use of stiffener plates, slotted plates and cruciforms within connections can greatly reduce the fatigue life of connections), ease of fabrication and ease of design. 36. 37. A connection formed from one thickened member through the connection and profile cutting and welding all other members to it was selected as the preferred fabrication option and the least fatigue sensitive detail, although more challenging to design. The thickened member through the connection is referred to as a ‘thickened can’.

In summary, the following design 38. 39. approaches, in order of preference, were applied to the different types of connections across the roof:

CIDECT with conservative assumption on mulitplaner correction factor Capacities calculation in accordance with AWS D1.1. Finite Element Analysis (FEA).

Ring beam The elevated ring beam is an integral component of the overall NST roof structure. The ring beam and the column pairs below form the primary support for the roof structure and act together to restrain the lateral thrusting forces of the roof dome structure.

The ring beam has a diameter of more than 310m and is formed from a 6m-wide by 1.5m-deep post-tensioned concrete beam with local thickenings to 2.0m deep at the column pairs below the roof support nodes (also referred to as ‘thrust blocks’). The thickenings deal with the large shear and bending forces being experienced by the ring beam due to the roof load transfer. The ring beam circumferential length is 40. approximately 1km.

36. Complexity and variation in the The roof structure is symmetrical in the NE/ fixed roof connection nodes. SW axis and asymmetrical in the NW/SE 37. Finite Element Analysis model of axis. The ideal geometry for the ring beam to a fixed roof connection node. balance the roof loads would not have been 38, 39. Thrust block under circular as constructed but more a faceted construction. pear shape between roof node positions. 40. Completed thrust block.

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93780_Text.indd 42 28/05/2015 15:48 41.

Both architecturally and practically, it was The roof was wind tunnel tested in quarter Ring forces transmitted determined to create a circular ring beam closed, half closed, three quarter closed to to ring beam at thrust block geometry with the ring beam column pairs investigate the possible effect of the

Resolution of forces working in portal action radially to resist intermediate position of the movable roof on at L3 ring beam any forces not funicular to the ring beam the wind load. It was found that the quarter circular geometry. closed roof generated higher edge pressures and overall loading on the roof when Movement joints The ring beam post-tensioning is developed compared to the other intermediate positions. via 14 tendons of 17 strands (each 15.2mm 1500 in diameter) placed in 2 rows of 7 tendons. Roof construction sequence Each post-tensioned tendon is approximately The construction sequence affects both the 6000 100m long and stressed from both ends. internal forces and deflections in the 14 post-tensioned 42. tendons The post tensioning ensures that under structure. An allowance of 10% utilisation service loads the ring beam remains un- on the fixed roof structure, excluding the cracked. Under the worst case ultimate load louvres, was assigned to deal with locked-in cases some cracking of the ring beam occurs stresses associated with the construction although it never goes into net tension at any methodology. section around the ring beam. A construction method was discussed with Wind loading potential steel subcontractors and outlined in Working closely with CPP (Sydney) the the structural tender drawings. This erection design team recommended adopting an sequence was assessed by the design team ‘influence surface’ method to determine and determined to produce locked-in stresses critical simultaneous patterned wind loads less than the 10% allowance. across the roof. This figure was advised to the bidding In this analysis, the time-histories of the steel subcontractors and the erection 43. wind pressure measured simultaneously over methodology of the winning steel the entire roof from the wind tunnel tests are subcontractor (Yongnam) developed to combined with structural weighting work within this allowance. 41. The stadium under construction. functions to determine the highest magnitude 42. Ring beam section and actions. and worst pressure distribution that cause 43. Wind loading analysis. critical design scenarios for direct application to the structural analysis. Such a method enables wind loads to be more accurately determined, considering the area and potential lack of correlation of the wind.

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93780_Text.indd 43 22/05/2015 10:36 Football / rugby Cricket Athletics

Football / rugby Lowering of Athletics concourse platform

44.

Moving tier systems Eight main sliding elements minimise the Acoustics During early design phases the Arup team number of gaps between seat modules The Arup acoustics team provided technical developed various options for the moving input into the acoustic design of both the As the lower tier moves inward from tier mechanisms. National Stadium and the wider sports athletics to football mode, a 12.7m gap precinct. For the National Stadium they opens up which needs to be filled for The design challenge was unique. With a generated a hybrid acoustic quality which pedestrian flow and to support permanent athletics track and the extended would ensure the best acoustic for both supplementary seating. requirements of football and cricket viewing, sports events and concerts. the moving tier systems needed to • A lifting mechanism was adopted to fill this accommodate a wide range of movements gap with 49 independent concourse In a sports venue the roar of the crowd is an (up to 12.7m) while maximising seating platforms. This meant introducing a trench essential part of the atmosphere. The capacity for each mode and being capable of below the platforms through which the acoustics of the stadium bowl were designed conversion from one format to another in a lifting mechanism could move with this in mind, providing natural target 48 working hours. Turnaround time was enhanced by reinforcement of the crowd noise by introducing a serapid machine to lift the including sound reflecting surfaces within The team investigated a variety of options platforms. The serapid is a mobile the space coupled with the level of acoustic of independently-movable segments in the proprietary lifting machine which runs in control that was necessary to ensure the PA lower 30,000 seat tier – from as few as eight, its dedicated 4m deep trench around the system would meet intelligibility targets and to as many as 50 – and a mixture of sliding full perimeter of the arena and lifts or concerts could be hosted without reflecting and hinged movement systems was lowers each of the concourse platforms sound to the field of play. developed and investigated. one-by-one Another issue for careful consideration was The design eventually adopted proved to be The adopted moving system reduced the the potential for heavy rain to generate noise. the best means of resolving the geometric number of sliding components and Detailed studies were undertaken to ensure complexity, as well as improving operational achieved simplification of sliding tier that the lightweight ETFE cladding would efficiency. This is how the system works: movement mechanisms using air skates, not impact on audibility of sound within the hydraulic jacks and PTFE sliding pads. National Stadium event space.

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93780_Text.indd 44 22/05/2015 10:36 45 46 44. The three modes of retractable seating and transition phase. 45. Singapore Chinese Orchestra Concert – first of its kind to be held in the newly opened National Stadium. 46. The National Stadium during the World Club Rugby 10s tournament – the first elite sporting event at the venue.

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93780_Text.indd 45 22/05/2015 10:36 Giant louvres provide Insulated metal roof Moving roof blocks out Roof designed to provide shade and rain reflects sunlight to solar radiation and naturally ventilated space protection to space reduce heat gain rain during event which reduces energy outside the stadium required for cooling

Cooled air is provided at each seat Moving roof opens when no event is on location providing low-energy in the stadium and provides natural comfort cooling for all spectators daylight required for pitch growth

47.

Blast engineering For some of the bespoke building, elements As both a world-class sporting facility and a response testing was undertaken to place to host major events, the Singapore accurately determine the structural response. Ministry of Home Affairs (MHA) identified These results were fed into the analysis to the stadium as a building of ‘national improve the reliability of the computational importance’. The stadium and its analysis. surrounding precinct therefore needed to be designed with long term resilience in mind. Bowl cooling Sustainability was central to the design of Under the design leadership of Patrick Sports Hub from the early stages of the Condon (Dragages Design Leader), Arup’s competition design. The team’s initial blast engineering experts determined the challenge was to make the stadium as blast hardening measures that could be energy-efficient as possible. Passive design 48. introduced with least effect on facility solutions were targeted first with shading to operations. seating, insulation to roof cladding and to the performance of the ETFE pillows of the The Arup, Dragages and MHA teams moving roof. assessed and refined the design, constructing Working in close collaboration with a extremely large numerical analysis models When it came to designing the bowl cooling leading UK university, the team designed a for critical structural elements like the dome system, the Arup team wanted to push the mannequin with temperature sensitive roof and the support ring beam and support boundaries of innovation while creating an artificial skin and tested it in a mock-up of columns. environmental solution that was technically three rows of stadium seating while robust and economic to build and run. simulating Singapore’s climate and the Potential threat scenarios were formulated, stadium’s proposed cooling system. The trial and the associated loading determined, and The seated volume of the stadium is only results confirmed the model could be scaled the response of the building structure and around 1/40 of its entire volume, so local up to a 55,000-seat stadium successfully. fabric assessed using sophisticated numerical cooling could achieve substantial reduction The team calculated that this localised analysis techniques. in energy use. When the team looked at what approach to cooling reduced energy use by defined comfort in a tropical climate they more than 60% when compared with found that whilst air movement was a typical modern American stadium. important it was most effective if delivered to spectators’ in a specific way.

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93780_Text.indd 46 22/05/2015 10:36 Local cooling provides greater flexibility in

Cooling times of lower seat occupancy because towers ventilation to unused seating can be switched off as required. The bowl cooling energy is then fully offset by a 700kWp Solar PV system. Although the bowl cooling system does not target specific comfort for athletes on the pitch, the moving roof reduces solar Chillers Condenser ring main intensity at ground level to less than one- tenth of open sky conditions.

Sustainable masterplan Cooling With the stadium at the centre of the towers Condenser precinct, the team’s mechanical engineers ring main Car park realised that an efficient solution needed to

Aquatic balance the intermittent energy demands of Centre the stadium with the everyday energy demands of the surrounding buildings.

Their proposal integrated thermal storage tanks into the design, which are pre-cooled before an event, and allow for peak demands Retail of the stadium seating to be met from the Multi-purpose Indoor Arena same plant that provides cooling to the adjacent office, retail, indoor arenas and aquatic centre.

The space-efficient centralised services

Thermal strategy developed at Sports Hub aligns with Chillers storage Offices the Singaporean Government’s long-term tanks Retail strategy for the future development of the city of Singapore and is a unique example of how different scale facilities, with different load requirements and usage patterns, can be designed to work off a combined system customised to meet regular and peak event load requirements.

Extensive landscaping has created a high- quality, natural waterfront environment around the stadium precinct. In fact, the Rainwater collected Sports Hub Consortium’s dedication to from roof achieving a sustainable design for the stadium and the Sports Hub precinct was recognised during the 2012 BCA Awards at which it was awarded ‘Green Mark GoldPlus’ Award.

Landscape Rainwater irrigation storage 49.

47. Low-energy design. 48. Solar radiation studies for roof performance. 49. Some of the stadium precinct’s award-winning sustainability measures.

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93780_Text.indd 47 22/05/2015 10:36 Fire engineering Pedestrian modelling The stadium is surrounded by adjacent sports Setting standards for the safety of spectators facilities and other buildings, and spectators within the precinct, and ensuring quality enter and exit the stadium via the Sports experience for people arriving and departing Promenade. To achieve the required fire from the various sports venues, was an safety performance, Arup’s team had to extensive piece of work for the pedestrian demonstrate that the Sports Promenade modelling team. Their work informed every provided equivalent performance to an aspect of the masterplan and in some external open-to-sky area to satisfy both instances the form and shape of the sports local code compliance and the requirements venues. of the Guide to Safety at Sports Grounds (5th edition) for a place of safety. The design of the precinct was tested against five onerous pedestrian movement scenarios, A similar process was required for the design including simultaneous events at the of roof steelwork, where for design and cost stadium, the aquatic centre, and the indoor 50. reasons, the preference was to avoid arena; in dry and wet weather conditions; intumescent paint. The scale of the roof and at low and high security levels. Testing meant the majority of steelwork was too and accepting the performance of these low Key areas of focus were the LED illuminated remote to require additional protection. probability occurrences demonstrated moving roof panels, which could project However the issue had to be addressed to the operational flexibility and design tolerance images onto the moving roof cladding base of the roof. regardless of event, function or weather. visible externally, and the LED lighting to highlight the characteristic pattern of the Both of these issues were solved through Each scenario was tested dynamically using roof cladding on the fixed roof scupper. detailed fire analysis which was used to Legion pedestrian simulation software. define and limit the fire load to the Sports The modelling predicted the movement of The lighting design requirements for the Promenade. This required limitations to be the 55,000 to 65,000 people within the site moving roof were carefully balanced with imposed on vehicles, a detailed assessment given their forecast origin and destinations. environmental modelling constraints. To of the natural ventilation achieved via the The combination of design, route choice reduce solar energy within the stadium a giant PTFE louvres and an agreed options, mode choice, operations and relatively opaque cladding surface was management routine for the area during infrastructure capacity created substantial required. However this worked against the events. and complex emergent movements which requirements of the moving roof lighting. had to be understood and communicated in For the moving tiers, the design challenge simple terms. Detailed modelling was done to balance was greater because of the susceptibility to internal visible surface temperatures against damage of fire protection applied to moving Performance outputs from the models light transmittance requirements for night components. Simplified structural analysis provided confirmation of capacity elements time illumination. Using a full-scale mock- was undertaken to narrow the scope of the such as circulation widths, queue zones and up of the moving roof, built on site, Arup finite element analysis to the worst-credible vertical transport capacities, as well as worked with Dragages’ sub-contractor to fire scenario. Subsequently, Strand 7 was layout and operational strategy. develop an optimised solution which relaxed used to conduct the non-linear structural the solar energy transmission to 8%, ensured performance in fire and fire protection The key areas of focus included circulation that internal surface temperatures didn’t minimised to a limited number of critical routes, holding space, weather protection exceed 40°C and allowed for an intensity of elements. and security screening. The final design was night time illumination to the top surface of tested across all areas and the overall results the ETFE cladding. The proximity of adjacent buildings meant were presented to the Land Transport that in many areas detailed analysis of Authority (LTA). The final design solution incorporates over spread of flame from one building to another 20,000 LED pixels, each illuminating a 1 x needed to be understood so that fire LTA acceptance of the performance formed a 1m square area of moving roof cladding. management could be operated on a major part of the approvals process for the Each 200 x 100 pixel screen has a level of building-by-building basis. For the aquatic final design. resolution that can project both static and centre a similar approach was developed to moving images and text. The completed that for the NST. For the retail areas, the Feature lighting NST moving roof lighting forms the largest escape strategy was subject to detailed At competition stage, the feature lighting addressable LED screen in the world. negotiation with the local authorities. was developed by Arup’s architects working with Light Cibles locally in Singapore. For the fixed roof scupper lighting, a similar Then Arup’s lighting team took the process was implemented using a full scale competition-winning imagery through the mock-up of the fixed roof cladding to test Urban Redevelopment Agency (URA) different lighting solutions. design review process to approval.

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93780_Text.indd 48 22/05/2015 10:36 The URA wanted the team to achieve a full wash to the scupper zone. Using the mock- up, the team demonstrated how a more discreet fixing could achieve the desired night time illumination affects. The final design solution incorporates more than 2,500 modular LED lights into the scupper cladding to create a well-integrated architectural lighting solution.

The final design, fabrication and implementation of the moving roof and fixed roof feature lighting was completed by Light 10 – a local lighting specialist.

Conclusion Arup has a long-standing track record of bringing the best of its international expertise to large projects around the world – and there is no better story to tell than its role in delivering the design of the Singapore Sports Hub.

A key tenet of design at Arup is the concept of ‘total architecture’ or holistic design. This philosophy was evident in the way design teams were organised to foster collective thinking in developing Singapore Sports Hub. It was apparent, also, in the effectiveness and efficiency of the collaboration with Dragages, DP Architects, 51. AECOM and the many other parties involved in bringing this magnificent project to fruition. This was truly a team effort.

Innovative ideas were nurtured, unique concepts were developed and delivered, to make the Sports Hub a venue perfectly matched to its location. It meets all its objectives: providing sporting facilities for the city’s residents, a spectacular setting for international sporting fixtures and world- class concerts and – perhaps most importantly of all – a home for the National Day Parade when the people of Singapore come together to celebrate their city’s independence.

A magnificent sporting and event facility, the Sports Hub will serve Singapore well for many decades to come.

52.

50. Pedestrian modelling was an important element of the design. 51, 52. Feature lighting makes the stadium a spectacular landmark in the city at night.

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93780_Text.indd 49 22/05/2015 10:36 Authors Clipsom, Lyonel Cochon, Joseph Correnza, Ben Cox, Nielsen, Zhang Ning, Lee Nissim, Jane Nixon, Emilia Chia Wah Kam, a Principal in the Singapore office, was James Cross, James Cruz, James Danatzis, Christopher Norin, Sabariah Norman, Chizoba Nwobodo, Azri Project Director and Qualified Person for the National Daniel, Lauren Davis, Gino De-Castro, Nelson De La Omar, Shahnaz Omar, Edwin Ong, Natalie Ong, Stadium roof. Cruz, Lim Deyuan, Antonio Diaz, Symur Diche, Rafaelle Oppido, Ayca Ozcanlar, Jin Pae, J Parrish, Andrew Henry is a Principal in the Singapore office and Antonietta Di Domenico, Chris Dite, Nick Docherty, Irene Pau, Joe Paveley, David Pegg, Mauro Pellegrini, he was the Project Manager. Jaymin Doe, Steven Downing, Steve Drane, Peter Li Peng, Daniel Peter-Birch, Neil Phipps, Anna Duggan, Natalie Dumbrell, Rose Dunlop, Chris Dunn, Piasecka, Douglas Pickering, Glen Plumbridge, Harris Clive Lewis was the lead sports venue designer. Leila Dunning, Alexander Edwards, Michael Edwards, Poirazis, Victor Polyik, Jason Poon, Kartigayen See Lin Ming, a Principal in the Singapore office, was Elad Eisenstein, Karl Ekberg, Kenneth Enright, Paul Poutelaye, Derek Powell, Karolina Pracz, Krista Qualified Person for the National Stadium seating bowl. Entwistle, Clint Faller, Michael Farrell, Puris Fazie, Prankerd, Maggie Puvannan, Chris Pynn, Chen Qian, Mike King, a Principal in the Singapore office, led the Ian Feltham, Gao Feng, Jing Feng, Leah Ferrari, Wang Qian, Kim Quazi, Virgilio Quinones, Ashish structural design team. Anthony Ferrau, Garth Ferrier, Shawnee Finlayson, Raikwal, Mithra Rajaratinam, Prakash Ramlal, Scott Kai Fisher, Vivien Foo, Gareth Forwood, Chris Fulford, Rathie, Robert Read, Brett Redgen, James Reed, Craig Malcolm Smith is an Arup Fellow and a Director in the Paul Fuller, Stephanie Fulton, Edwin Fung, Peter Reid, Roland Reinardy, Jochen Ristig, Christian Rivera, London office. He led the urban planning team. Gabor, Vellachi Ganesan, Mireille Gasking, David Eric Rivers, David Rock, Rommel Rogero, Marius Scott Munro, an Associate Principal in the Singapore Gaweski, Sacha Gebbie, Jan Glasmeier, Riika Graf, Roman, Pablo Romero, Jonathan Rose, Russell Ross, office, led the bowl cooling design. Konstanze Grammatikos, Caroline Grandjean Thomsen, Ken Roxas, Xavier Ryan, Ali Sadeghi, Karol Sahagun, Ruth Wong, an Associate Principal in the Singapore Madeline Gray, Tamasin Gray, Phillip Greenup, Joanna Sutomo Salim, Richard Salter, Katherina Santoso, office, led the fire engineering team. Gregorowicz, Michael Greville, David Griffiths, Shaina Saporta, Wisnu Saputra, Catherine Sarah Katherine Gubbins, Philip Guthrie, Andrew Hall, Roberts, Sathi Satcunan, Per Sauer, Rob Saunders, Peter Hoad, a Principal in the Singapore office, led the Barnaby Hall, Liana Hamzah, Graeme Hanshaw, Nick Sebastian Schulz, Jamie Scott Toms, Manan Shah, blast engineering team. Hardy, Fraser Harland, Hasnita Hashim, Rebecca Sundip Shah, Helen Shiell, Jon Shillibeer, Hiew Nick Boulter, an Associate Principal in the Melbourne Hatchadorian, Evan Hatzikalimnios, David Hawley, Siaw-Ling, Jasdeep Sidhu, Martin Simpson, Paul office, led the acoustic design team. Andrew Henry, Emma Heyes, Mat Hiley, Jarrod Hill, Simpson, Christopher Sims, Alexandra Sinickas, Ang David Hiller, Aris Himawan, Patrick Hinde, Arge Siow-Ting, Benjamin Sitler, Li Siyu, Christopher Project Credits Hipolito, Pavel Hladik, Jamie Hladky, Peter Hoad, Sloman, Andrew Smith, Malcolm Smith, Rob Smith, Owner: SportsHub Pte Ltd; Client and Main Contractor: Charlie Hogg, Guy Hollingum, Josh Howe, Peter Howe, Tara Smith, Gladys So, Jose Soares, Chong Sok Poi, Dragages Singapore Pte Ltd Architect (Sports Venues): Ng Hui-Xin, Sarah Huskie, Michael Hutchison, Chee Angelo Spampinato, Ed Spraggon, William Spraggon, Arup Associates & DP Architects Pte Ltd Architect Hwei Nu, Steve Ingle, Kevin Ip, Mellissa Ismail, Peter Martin Stanley, Paul Stanley, Zoe Stewart, David (retail, leisure, office):DP Architects Pte Ltd James Llewelyn, Toby James Mccorry, Luke Jarvis, Stirling, Jeremy Sue, David Sum, Pippa Summers, Sunil Mechanical & Electrical Engineer: Squire Mech Pte Ltd Henry Jeens, Alex Jenkins, Russell Jessop, Xu Jingfeng, Ranjith Sangakkara, Evi Susanti, Mak Swee Chiang, Landscape Architect: AECOM Steel Contractor Jin Hong Geng, Phil Jones, Sylvane Joseph Mark Swift, Corrine Tan, Geraldine Tan, Mac Tan, Willy (National Stadium, OCBC Aquatic Centre and Arena): Maduranayagam, Ryan Judge, Yusof Junaidah Mohd, Tan, Bernard Tay, Jocelyn Tay, Larry Tedford, Deosette Yongnam Engineering & Construction Pte Ltd Hiew Ka Fui, Kelvin Kan, Deepak Kandra, Sigmund Ternida, Nagadurai Thangavel, Andra Thedy, Will Sports venue design, civil, structural, fire and maritime Kasten, Subash Kathiresan, George Kazantzidis, Debra Thickett, Scott Thirtle, Luke Thomas, Patricia Thorpe, engineering, geotechnics, acoustic, audio visual and Kelly, Lim Keong Liam, Khisan Khan, Liew Kim Hoe, Jun Tian, Madeleine Tillig, Sean Tobias, Pavel Tomek, multimedia, building physics and environmentally Mike King, Wong Kin Puan, Alex Kobler, Heng Kok Colleen Tompkins, Roland Trim, Choong Ts, Aaron Tse, sustainable design, security and risk consulting, lighting Hui, Tan Kok Kwang, Lum Kok Mun, Tan Kok Yong, Ko Andrew Tulen, Louise Turner, David Twiss, Mutlu design, advanced technology and research (moving Sing Yen, Milena Kovac, Marek Kowalski, Lukasz Ucuncu, Mart Umali, Jbu Uy, Eugene Uys, Luke Vance, structures), specialist technical services (sports lighting, Kuder, Freya Kumm, Franklin Kwan, David Lakin, Manja Van De Worp, Felipe Van Klaveren , Karthik bowl cooling, pedestrian modelling and arena Lukki Lam, Wilson Lam, Tilly Langley, Ida Larrazabal, Venkatesan, Mathew Vola, Henry Vong, Chia Wah-Kam, consulting): Arup – Nizar Abdul Rahim, Hector Abella, Phil Lazarus, Phuong Le, Rhodri Lea, Elizabeth Kwok Wai Cheong, Leo Waible, John Waite, Matt Riccardo Abello, Sonja Abhyankar, Ivy Abo, Paul Leaming, Leann Lee, Nicholas Lee, Richard Lee, Walden, Grant Wang, Matthew Wash, Chris Webb, Adams, Kelly Adighije, Pedro Afonso, Ian Ainsworth, Sebastian Lee, Craig Leech, Forest Lee Flager, Peter Christian Webb, Chua Wee Koon, Lin Wei, Ruben Michael Alder, Andrew Allsop, Joseph Amores, Erik Lees, Kevin Legenza, John Legge Wilkinson, Chris Welschen, Will Whitby, Gary White, Peter White, Ryan Andersen, Key Anderson, Banu Aydin Anderson, Lewis, Clive Lewis, Trevor Lewis, Sean Liao, Liam White, Sieb Wichers, Dileep Wijewardena, Rupinder Richard Andrews, Christine Ang, Mark Arkinstall, Jake Lidstone, Hasta Lie, Astee Lim, William Lim, Tang Lim Wilkhu, Robert William Murphy, Huw Williams, Nick Armitage, Paul Aspinall, Sammy Aung, Hugh Austin, Mei, Angie Lin, Mark Lindsay, Wong Ling Chye, See Williams, Berlina Winata, Mo Wing Sze, Ruth Wong, Jennifer Austin, Martin Austin, Tharakan Babu, Peter Lin-Ming, Nur Liyana Ahmad, Priscilla Loh, Choi Lok Andrew Woodger, Andrew Woodhouse, John Woodman, Bailey, Warren Balitcha, Hamish Banks, Lesley Banks, Ching, Geena Loke, Kate Longley, James Longsden, Darren Woolf, Hayden Wright, Li Xiang, Wu Xiaofeng, Alma Banuelos, David Barker, Daniel Barnes, Greg Alberto Lorenzo, Andre Lovatt, Cecilia Low, Josephine Wu Xuchao, Luo Xueni, Helen Yan, Anna Yeadon, Barnes, Bella Basaglia, Gregor Beattie, Jeanine Luarez, Farong Luo, Christopher Lydon, John Lyle, Mandy Yeo, Zhao Ying-Ying, Colin Yip, Heng Yong, Tan Benjamin, Daniel Bergsagel, Nilda Bernal, Nick Malcolm Lyon, Tim Lyon, Robert Macri, Serene Mah, Yoong Heng, Ray Young, Young Jie Yu, Simon Yu, Bertram, Monika Beyersdorff, Felix Beyreuther, Sean Maher, Juan Maier, Mukunthan Manickavasakar, Christa Zacharia, Han Zahara Amed, Enrico Zara, Zaw Marieanne Bird, Sudhir Bommu, Nick Boulter, Amy Mirjana Marjanovis, James Marsden, Olan Masula, Jin Zaw Aung, Daisy Zhang, Yushu Zhang, Pawel Zielinski, Boulton, Peter Bowtell, Ashley Bracken, Ryan Brate, Matsumoto, Alastair Mcconville, Kate Mcdougall, Mohsen Zikri. Fergal Brennan, Michael Brizell, Trevor Buckley, Stuart Alistair Mcgill, Sean Mcginn, Michael Mcgowan, Bull, Richard Bunn, Stephen Burrows, Melissa Burton, Cameron Mcintosh, Jason Mckenzie, Lisa Mcmillan, Image Credits Edward Caine, Gray Canning, Marc Caplan, Tristram Brendon Mcniven, Andrew Middlebrook, Roger 1-2, 4, 7-19, 22-24, 26, 28-39, 42-47, 49-50, 53 Arup; 3, Carfrae, Lee Carl, Efren Cerrero, Cha Eun-Ju, Lochlan Milburn, Robert Milne, Tey Ming Jong, Bruce Moir, 52 Poh Yu Khing; 25, 40, 41 Clive Lewis/Arup; 5-6, 20, Chalmers, Rachel Chaloner, Chris Chambers, Rick Adam Monaghan, Ben Moore, Jon Morgan, Muny 51 SHPL/Oaker; 21, 27 Christian Richters. Chana, Renuga Chandra, Wayne Charles, Angela Chen, Morgan, Peter Morris, Richard Morris, Jonathan Joy Cheong, Patrick Cheong, James Chimeura, Jason Morrison, Hugo Mulder, Scott Munro, James Murtagh, Chin, Michael Chin, Alecs Chong, Bee Choo Lloyd, Lai Josh Neil, Chris Neilson, Kai Nelson, William Newton, Chuen Hien, Lai Chun Moon, Kevin Clinch, Daniel Derek Ng, Rachel Ngu, Eliza Niamh Southwood, Jack

50 The Arup Journal 1/2015

93780_Text.indd 50 22/05/2015 10:36 The Arup Journal 1/2015 51

93780_Text.indd 51 22/05/2015 10:36 Bosco Verticale – a forest in the sky

Location Authors Milan, Italy Luca Buzzoni James Hargreaves Valeria Migliori

1.

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93780_Text.indd 52 22/05/2015 10:36 1. View of the residential towers of Bosco Verticale in Porta Nuova, Milan. 2. Plaxis analysis of the existing tunnels and surrounding soil underneath the site.

Introduction Arup’s role diaphragm wall typologies with many Bosco Verticale – literally the vertical forest Arup provided structural and geotechnical different temporary restraint solutions – is the wonderfully evocative name for two designs and consultancy on acoustics, (e.g. soil nailing with different number and residential towers in Milan, Italy. Rising vibrations, ground-borne noise and length of ground anchors, temporary 110m and 76m from the ground, these new tunnelling. This included advanced design propping from within the site and cantilever homes are located in Porta Nuova, one of the solutions relating to the effects of two solutions with no temporary restraints). largest urban redevelopment projects in railway tunnels under the site which required Europe where they will eventually form part dedicated design of a base-isolation system The existing tunnels were assessed through of a new residential and commercial area for the main buildings. Arup’s Milan office, desk-studies, surveys and in-situ tests to interspersed with parkland. where most of the design was developed, allow detailed analyses of the structure co-ordinated the project with teams from the during the planned construction of the new The balconies of the apartments, duplexes Midlands Campus and London contributing. buildings typically only 3.5m above the and penthouses extend outwards by tunnel crowns. The behaviour of tunnels was approximately 3.5m to host an abundance of Initially, Arup was appointed for analysed for the direct effect of the new trees, shrubs and plants, creating the overall geotechnical and structural design from buildings; the construction of diaphragm effect of a huge hanging garden. In total, concept to construction, including site walls and excavation; and the indirect 900 trees measuring between 3m and 6m support. Specific peculiarities of the site and loading effect of the towers. The analyses have been planted, together with 5,000 design required input from other Arup predicted the evolution of settlements and shrubs and 11,000 floral plants on terraces experts, however. Arup offices in Europe and stresses in the tunnels with an incremental up to the 27th floor. the Americas were involved in assessing the finite element load-analysis carried out effects of the two metro tunnels beneath the with Plaxis software. Arup worked with Boeri Studio and Hines site; the potential acoustic and vibrational Italia on the design and development of this effects of trains on the buildings and design new model for regenerating the urban of mitigating measures; and advice on wind Vertical environment. Its intention is to inspire tunnel tests relating to the structures and the displacements greater biodiversity to combat Milan’s trees, including structural design of safety (Uy) increasingly high levels of pollution. The elements for the biggest trees. 10,000 vast amount of greenery on the building will 8000 6000 create oxygen and humidity while absorbing The holistic integrated approach Arup 4000 CO2 and dust particles. The design also brought to the project helped define options 2000 includes photovoltaic systems to provide for solving unconventional problems in 0 -2000 renewable energy (Fig 1). demanding situations on a compact and -4000 challenging site. -6000 Following the proposal to create Bosco -8000 Verticale at Porta Nuova, 70% of the area Structures and geotechnics designated for redevelopment has been Despite the good soil characteristics of the assigned to public parkland. The rest of the site and limited influence of the water-table, 2. complex will comprise new public, several physical and geometrical constraints residential and commercial buildings, required thorough geotechnical design. In including the new Italian headquarters particular, detailed interaction analysis with for Google. the existing metro tunnels and the adjacent buildings was required (Fig 2).

The presence of existing buildings adjacent to the site, the M2 metro tunnels underneath the North portion of the site and the new Metro 5 tunnel under construction on the east side, required specific design of several

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93780_Text.indd 53 22/05/2015 10:36 During construction of the buildings, the train tunnels were monitored to control possible unexpected effects and verify that real behaviour matched numerical predictions. The monitoring system was wirelessly connected to a dedicated network that enabled continuous checking of the performance of the existing structure against defined limits. In case of undesired behaviour, two different levels of alarm were pre-defined to alert the company running the trains and advise on the need for further checks or temporary stoppage of the line (Fig 3).

The two residential towers have shallow foundations, thanks to good soil performance and a concrete structure. (In the diagram, tower ‘Confalonieri’ or Tower D is 76m tall and has 20 floors above grade, tower 3. ‘De Castillia’ or Tower E is 110m tall and has 27 floors above grade). Concrete was specified with grade from C28/35 up to C60/75 for the columns and for some of the base walls of the cores (Fig 4).

For the 2m thick foundation raft of tower ‘E’, C30/37 low-heat pozzolanic cement mix was requested and one continuous pour of 2,100m3 was adopted in 12 hours. The development of heat within the pour (at the end of June with an external temperature between 20°C minimum at night and 37°C maximum during the day, protected with thermal insulating panels) was monitored with thermal couples and the maximum difference of temperature between the core and the surface was 20°C with a peak at the core of 65.4°C.

For Tower D the base isolation system illustrated in the next section of this article required a double foundation scheme with a 1.6m thick raft and a suspended false- foundation raft sitting on springs.

Both towers have an eccentric concrete stability core, perimeter rectangular columns 4. and post-tensioned concrete slabs and beams. The system adopted for the slabs and The typical thickness of the slabs is 28cm 3. Revit model of the development beams allowed Arup to reduce the depth of both inside the apartments (with a maximum with the two existing tunnels in the elements, control deflections and span of approximately 10m) and in the the foreground. vibrations and improve the capacity of the terraces (where the cantilevers are up to 4. Pouring of the foundation raft of tower E big cantilevers with the relevant design loads 3.5m when measured perpendicular to the requested for the terraces. columns’ line or approximately 7.5m in the corners). The terraces have been designed for a live load of 4kPa and - due to the trees and planters - for a uniform line-load, in addition to the structural weight of the planters, of 13kN/m and 7kN per tree every 3m, centre-to-centre.

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93780_Text.indd 54 22/05/2015 10:36 The presence of trees on the terraces has Finally, despite the low seismicity in Milan additional important effects on the structure. (i.e. approx. 0.05g peak ground acceleration In addition to the imposed dead load, the with a likelihood of exceedance of 10% in effects of wind transmitted by the trees to the 50 years or 475 years return period) all the slab and induced vibrations had to be taken buildings in the Porta Nuova redevelopment into account. Wind loads on the trees were have been designed for seismic resistance, estimated based on literature information with a special focus on Tower D. This was and best practice then confirmed through because the tower is isolated at the base to wind tunnel tests. mitigate the effects of ground-borne vibrations and noise induced by the metro Unbonded post-tension was adopted initially trains, as illustrated in the following section. both for slabs and beams. However, bonded The isolation system in the tower shifted the post-tension was eventually used for the first natural period from approx. 1.5s to slabs to provide additional safety against almost twice as much at 2.9s (Fig 7). 6. possible corrosion of the live end of the stressing tendons that for the slabs are Base isolation, in addition to mitigating the protected only by the parapet cladding and effects of trains pass by, enhances the might be exposed to weathering should the seismic performance of the structure by protecting anchorage block fail. Beams are increasing the resilience of the building and always within the façade line and beam its structural and non-structural components tendons’ ends can never be exposed so to earthquakes. unbonded post-tension was confirmed. However, as will be explained in the next Because of the layout of the terraces, sections, the increased flexibility of the different every six levels, cantilevering slabs building could introduce undesired effects were poured on a self-supported due to wind. These potential effects were cantilevering scaffolding which didn’t rely mitigated with viscous dampers that helped on support from the levels below but only on increase the intrinsic structural damping up the proper connections to the internal portion to 1.5% critical, as peak acceleration would of one single slab below and to the columns have exceeded the acceptable limits set by (Figs 5–6). the international practice and codes. 7. 5. 5. Tower E under construction. 6. Self-supported cantilevering scaffolding by Peri. 7. Dynamic analysis of Tower D.

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93780_Text.indd 55 28/05/2015 15:50 Base isolation system Description The Porta Nuova site is above line M2 of the Milan Metro system between the Garibaldi and Gioia stations in central Milan. The line comprises two tunnels with a tunnel crown elevation less than 20m below the ground surface.

Rail systems generate ground-borne vibration (GBV) partly because of irregularity in the wheel tread and rail head surfaces and partly because of the dynamics of the track structure and vehicles. The transmission of rail GBV to the building structures is a particular risk on this site given the close proximity of the track to the ground surface combined with the fact that the buildings have basement structures. It is also a risk for this development since several 8. of the buildings are located over or close to the metro tunnel alignment in plan. and the need for isolation confirmed in the The risk can only be fully evaluated and first instance. The vibration survey also have meaning in relation to the performance enabled the vibration characteristics of the criteria of the building. The building site to be determined, in particular the function is residential and in Italy the frequency of the GBV energy arising from vibration criteria applicable to the comfort metro train pass-by events, which helped to and perception of humans in buildings is inform the selection of a suitable frequency covered by the UNI 9614:1990 code. The for the base isolation. It was necessary to acoustic criteria mean that structure-borne measure the vibration at elevations noise has to be discriminated from air-borne corresponding to the foundation structures noise. The latter is essentially what is and hence bore holes were created on site. transmitted into the building through the The accelerometers were placed into façade and is not related to GBV. The GBV, special canisters, designed by Arup, and generated mainly by the metro, is transmitted lowered into the bore holes. The vibration into the building structure causing the walls data was processed so that it could serve its and floors of residential spaces to vibrate main purpose which was to be used as a which in turn generates sound pressure in the dynamic load in the subsequent modelling enclosed air-space; this is known as and analysis. structure-borne noise. Acoustic criteria generally set limits on total noise – i.e. The system air-borne plus structure-borne. Base isolation systems involve floating the building structure on an array of resilient 9. This risk was mitigated by designing a elements which can be elastomer bearings or suitable base isolation system and helical steel springs (Figs 8–9). To meet the 8–9. Helical steel springs performance evaluation was carried out at criteria for this project it was predicted that isolators installed in the the design stage to show conformance with isolation frequencies of 3.5Hz or lower foundations of tower D. the vibration and noise criteria. Base would be necessary, which is only possible 10. Tower E isolation was incorporated into the design of to achieve with helical steel springs. Base several buildings on site, including Tower D isolation works by transferring vibration on for which vibration isolation had the active side (the lower/ground side in this implications for the seismic and wind case) into movement of the springs so that performance of the building because of the structural vibration on the passive side height of the structure. (the building structure) is reduced. The effect is frequency dependent and as frequency Site assessment increases the amount of isolation increases Vibration surveys were carried out on site - an important consideration for structure- before construction started so that the site borne noise which can be problematic at vibration performance could be quantified frequencies in the range 25 to 200Hz.

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93780_Text.indd 56 22/05/2015 10:36 A special seismic isolation product was The first stage of this process for Tower D therefore considered which although it had a was to develop a system that would isolate higher isolation frequency than ideal, at vibration. The second stage was to consider 3.1Hz, had a much higher stiffness ratio of 7 if and how this system must be modified so which was shown to lead to higher, but that the building performance under seismic nonetheless manageable, seismic demand for and wind loads conformed to those criteria. the building structure. The higher isolation A feasibility study was performed ahead of a frequency inevitably led to less vibration commitment to incorporate the isolation isolation, which had to be checked. It was within the structural design. also necessary to check the building performance under wind loads and in the The important direction for the seismic loads presence of the 3.1Hz seismic isolation. is horizontal and hence the shear stiffness of the isolation system needs to be relatively The structural design had to be modified to low, a common feature of seismic base enable spring elements to be placed in the isolation. As noted above this means the cut-plane and on the principal structural load ratio of vertical to horizontal stiffness must paths in plan. (Access to the spring units is be high for the spring units. necessary for installation, adjustment and maintenance in future years). The spring Wind loads contain most energy at very low units selected were also pre-stressed frequencies and hence interact with tall according to the vertically supported loads. buildings which have sway modes at these This means that the springs do not deflect as frequencies. Hence motion at the top of the building structure construction Tower D was the most important progresses above the springs. The pre-stress consideration. The base isolation system in each spring unit had to be released upon effectively removed stiffness from the construction completion to realise the foundation structure of Tower D leading to a isolation function. reduction in the natural frequency of the sway mode and greater movement. Such The spring units are under high vertical modes have little structural damping partly 10. static load from the building structure and because the base isolation system also has hence tend to be held securely in place very little damping, with structural damping In the case of Tower D isolation frequency vertically and horizontally due to friction. in the spring elements expected to be less of 2.4Hz would be required to meet the However, a resilient adhesive-coated mat is than 1% critical. The building structural criteria in full. When considering spring placed at the top and bottom of the spring mode also is expected to have little structural products, the isolation frequency is related to units to ensure the springs are securely damping since it tends to be floating on the the axial spring stiffness as this is the stiffest located. springs and while there is strain energy in direction for helical steel springs and the structure this is small compared to say a A further important aspect of the isolation because it is very common to need to isolate conventional cantilever type structural mode. design is that it must not be impaired by vibration in the vertical direction. Helical bridging the cut-plane with a structural load The solution was to incorporate an array of steel springs are simple flexible structures path. For the building structure itself, this viscous dampers within the cut-plane to and hence have horizontal stiffness which is will obviously not be the case, so increase the intrinsic structural damping of generally less that the vertical stiffness. The architectural detailing must take account of 1.0% critical to an effective structural ration of vertical to horizontal stiffness, or this by either avoiding the bridging damping of 1.5% critical. In this way energy stiffness ratio, was 2.5 for the 2.4Hz altogether or where it is necessary ensuring of wind-induced sway motion could be isolation frequency product. the structure is very flexible. absorbed to the point where it was possible The standard isolation frequency for spring to conform to NBCC (National Building Analyses and design units is 3.5Hz. These are widely available Code of Canada) criteria. To evaluate the performance of the isolation and cost-effective. Spring products of 2.4Hz system at design stage and compare it with The performance of the system was tested are non-standard and more expensive. the performance criteria, it was necessary to for GBV, total noise and wind vibrations However, the seismic loads for the building develop a finite element model of the after construction to prove the adequacy of must also be accommodated by the isolation building structure and carry out dynamic design and validate the initial assumptions system and horizontal loads, in particular, analysis. The analysis also enabled the and analysis criteria. Actual performance place the greatest seismic demand on a tall required isolation frequency to be confirmed showed a very good fit with the design building such as this one. Hence low and the design of the spring array developed numerical simulations. horizontal stiffness was an important so that the springs were loaded evenly within requirement of the isolation system and a the cut-plane and the loads were within the stiffness ratio of 2.5 was studied and found spring capacity. to be too low.

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93780_Text.indd 57 22/05/2015 10:36 The trees 11. On the balconies, restraining 14. Rendered view of the The effect of the trees on the terraces of cables for the trees are clearly restraining device for the Bosco Verticale on the structures and overall visible. biggest trees. safety of the design were assessed through 12. Physical model at 1:100 scale 15. Installation process of a for wind tunnel tests at Politecnico tree in Tower E. detailed analysis including two sets of wind di Milano. tunnel tests. 13. Wall of Wind at Florida International University for The different species selected were analysed real-scale tests on trees. and possible geometries defined, in order to allow the definition of the wind forces and the likely point of application. Working with the botanical consultant for the project, the expected maximum surface exposed to wind was defined for all the species, together with the location and height of the resulting centroid.

After Arup’s wind engineering team in London had defined a detailed wind climate analysis for the site, the structural stability of the trees was tested in two different wind tunnel test campaigns.

The first set of tests in the wind tunnel facility of the Politecnico di Milano assessed the forces on the trees in a 1:100 scale model (Fig 12). The value is a compromise between the need to build models as large as possible and keep low blockage values (the boundary layer test section in the wind tunnel is 14x4m).

The large dimensions of the model are useful both for reproducing the geometric details and to achieve a Reynolds Number that is the most meaningful of full-scale conditions. The defined geometric scale is also compatible with the scaled simulation of the boundary layer. The Towers D and E are manufactured as a ‘rigid aerodynamic model’ – a static model that reproduces the geometry of the full-scale structure (aerodynamic surfaces and details). The model of the buildings includes trees on the terraces chosen to have aerodynamic drag coefficients equivalent to full-scale trees, according to available literature.

Wind tunnel tests were carried out in a scaled simulation of the natural wind characteristic of the site. For this purpose the existing and planned buildings in the surroundings were modelled. (The most significant volumes within a radius of 600m assuming a centre among the towers). The whole area of the towers and the surroundings were placed on a turntable (diameter 13m). In this way it was possible to investigate all relevant wind exposures defined without any change in the test set-up. 11.

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93780_Text.indd 58 22/05/2015 10:36 Aerodynamic forces on a few selected trees Conclusion were measured by means of purpose-built Bosco Verticale is a novel approach to an dynamometers. The instruments measured issue facing many cities around the world – the components of the aerodynamic force how best to mitigate the effects of urban parallel to the plane of the floor. In addition, pollution while providing homes for an speed-up measurements on the terraces and expanding population. The result is a roof were performed using 15 Irwin probes. visually stunning architectural solution, These instruments allowed measurement of providing sustainable and ecological the magnitude of the wind velocity at a given benefits. position at a height of 20 mm from the floor of the terrace (corresponding to a height of Winning the International Highrise Award 2m in full-scale). 2014 underlined Bosco Verticale’s 12. international significance. This award, The second set of tests, carried out in the sponsored by the Deutsches open-flow facility of Florida International Architekturmuseum, the City of Frankfurt University, was designed to verify the forces am Main and Deka Bank, is presented every on real trees. The study was carried out with two years to the world’s most beautiful and the 12-fan Wall of Wind (WoW) hurricane innovative high rise. simulator located on FIU’s College of Engineering and Computing Campus in Authors Miami (Fig 13). Luca Buzzoni is an Associate Director in the Milan office where he leads the Structural Engineering Team. Following the results of the analyses and He led the overall engineering team for Bosco Verticale. James Hargreaves is an Associate Director in the 13. tests, three restraining devices were designed: all the trees have temporary elastic Midlands Campus and leads the structural dynamics business. He led the analysis and mitigation of bands that connect the root bulb to a steel vibrations and structure-borne noise for Bosco Verticale. mesh embedded in the soil; all the medium Valeria Migliori is a senior structural engineer in the and large trees have a safety cable to prevent Milan office. He was project engineer for Bosco the tree from falling in case the trunk breaks Verticale. as a consequence of large wind-storms; the largest trees, in locations most exposed to Project credits Client: Hines Italia SGR SpA per conto del fondo Porta wind, have a steel safety cage that restrains Nuova Isola. Structural engineer and multidisciplinary the root-bulb and prevents it from engineering design: Arup – Lorenzo Allievi, Andrew overturning under the most severe Allsop, Matteo Baffetti, Enrica Barzaghi, Luca Buzzoni, windstorms (Fig 14). Immanuel Capano, Luca Dellatorre, Xiaonian Duan, Silvia Ferrero, Patricio Garcia, James Hargreaves, Simon Hart, Sam Jewell, Hyuk Il Jung, Oronzo While the elastic bands are designed as a Lacirignola, Yi-Jin Lee, Ziggy Lubkowski, Enrico temporary restraint until the roots are fully Manganelli, Lorenzo Marengo, Alvaro Martinez, developed, the restraining systems for the Riccardo Merello, Paolo Micucci, Valeria Migliori, Phil largest trees are designed for the entire Mudge, Angelo Mussi, Nick O’Riordan, Adrian Passmore, Vincenzo Patruno, Giuseppe Pelagalli, expected life of the building to provide a Roberto Persio, Francesco Petrella, Alberto Rossi, Luca permanent safety solution for the stability of Rossi, Jamie Talbot, Maurizio Teora, Salvatore the trees. Tessitore, Roland Trim, Francesco Uggetti, Michael 14. Willford, Peter Young Architect: Boeri Studio (Stefano The different solutions were soft-tested, with Boeri, Gianandrea Barreca, Giovanni La Varra) now 15. Stefano Boeri Architetti and Barreca & La Varra fully detailed 3d mock-ups and real mock- Landscape and Botanical Consultants: Laura Gatti and ups, to prove ease of installation and Emanuela Borio General Contractor: ZH General possible interferences with non-structural Construction Company SpA Base-Isolation System requirements before starting production. The Supplier: Gerb. connections of the steel cages to the concrete Image credits parapets, for instance, were coordinated with 1–4, 7, 10, 11, 14, 15 Arup; 5, 6 Peri; 8–9 Gerb; the water-proofing requirements of the 12 Politecnico di Milano; 13 Florida International planters and approved by the insurance University. company responsible for the water-tightness of the system (Fig 15).

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93780_Text.indd 59 28/05/2015 15:51 UCSF Medical Center at Mission Bay

Location Authors Mission Bay Campus, University of California, San Francisco Alisdair McGregor Raj Daswani

1.

Introduction The medical center opened on 1 February UCSF Betty Irene Moore Women’s California has seen an upsurge in new 2015 – on time, under budget and widely Hospital for cancer care, specialty surgery hospital design and construction in recent acknowledged as an exemplar of best and select outpatient services; and a 36-bed years driven by regulatory requirements to practice in hospital design. It is one of the birth center replace or upgrade existing facilities to new first hospitals in California to be awarded UCSF Ron Conway Family Gateway seismic standards. University of California, LEED Gold Accreditation (Leadership in Medical Building San Francisco (UCSF) has taken the Energy and Environmental Design). opportunity to develop its medical research An energy center, helipad, parking and campus at Mission Bay to meet these This article focuses on the sustainability support services. standards and simultaneously create an aspect of Arup’s brief and the integrated exceptional level of sustainability. delivery concepts Arup and UCSF The patient bed units are arranged along introduced to achieve such outstanding wings facing north and south above a Arup has worked on the project from the results. podium containing the diagnostic and outset, integrating sustainability and project treatment functions. This orientation delivery across the site and providing The project optimises daylighting potential. structural, mechanical, electrical, and UCSF Medical Center at Misson Bay is plumbing engineering services for the located on a 14.5 acre site in the former dock UCSF Medical Center at Misson Bay medical center complex adjacent to the and warehouse area of the city. It comprises: provides comprehensive diagnostic, biomedical campus. interventional and support services, and uses UCSF Benioff Children’s Hospital, advanced robotic and imaging technology San Francisco, with emergency and during surgery, in an environment centered pediatric primary care and specialty on the compassionate care of patients and outpatient facilities (183 beds) their families. Integration with the biomedical campus strengthens collaboration UCSF Bakar Cancer Hospital for adult between researchers and clinicians. patients (70 beds)

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93780_Text.indd 60 22/05/2015 10:36 1. UCSF Medical Center at Mission Bay opened on 1 February 2015, on the target date set six years previously. 2. Daylight, fresh air and green space is accessible from all patient, caregiver and public areas.

Designing for health Arup subscribes to the view that a sustainable healthcare facility minimises negative health impact on the surrounding environment while promoting healthy outcomes for patients and staff. This is different from defining sustainability in terms of a LEED rating because there are unique opportunities and challenges in developing sustainable design for healthcare. Reducing the risk of airborne infection transmission and creating more therapeutic environments, for example.

The Green Building Council, which runs the LEED certification scheme, recognises that designing for health is an integral part of sustainable design. This is evidenced by the fact that the US Green Building Council, Northern California Chapter, launched the Building Health Initiative in 2014 with Arup as a founding member. (For more 2. information, please visit www.usgbc-ncc. org/buildinghealthinitiative). Specific targets that followed from the views, minimising solar gains, and creating a Achieving a fully-sustainable hospital principles included commitments to create highly thermally and visually comfortable requires an integrated team approach, so a healthy, vibrant habitats to increase environment were established early in the series of workshops was organised at the biodiversity and a pledge to ensure the process to frame an iterative ‘optioneering’ start of the UCSF project to enable the project did not use potable sources of water process whereby various façade designs design team and UCSF clinical and for irrigation. The new hospital must achieve could be qualitatively and quantitatively operational staff to determine key goals and 50% reduction in energy use compared with assessed and improved. strategies. Using benchmarking studies of a typical hospital of similar size and provide current best practice, leading-edge abundant access to daylight, fresh air and As the architectural team developed glazing, discoveries from evidence-based design green space from all patient, caregiver and shading and layout options, the engineering research, LEED guidelines, the Green Guide public areas. A clear, rigorous protocol was team guided the design with a set of peak for Healthcare (www.gghc.org) and the to be established for assessing all materials load thresholds, each of which – if exceeded specifics of the site and programme, the and products used. – would trigger a more energy-intensive, and workshops delivered the following set of physically larger, perimeter HVAC (heating, principles. They decided UCSF Medical Energy and thermal comfort studies ventilation and air-conditioning) system. Center at Misson Bay must incorporate: Energy reduction is key to sustainable healthcare design. Although the cost of The lighting team tested the options for Light and views energy is far less than staff costs, energy natural light levels and penetration, further Fresh air costs are still significant in a low profit- informing the design with indicators such as the potential for artificial light reductions. Green space margin business. Healthy materials Arup’s engineering, lighting and Energy and thermal comfort studies • Clear wayfinding architectural teams worked closely with the were carried out to highlight the lifecycle, architect to optimise the façade design economic, and qualitative benefits of • Anticipatory design (or flexibility during the schematic/concept design phase. elements such as high-performance for future change). Common goals of maximising daylight and glazing and external shades.

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93780_Text.indd 61 28/05/2015 15:52 3.

Analysing heat gain These diversity factors were developed Variable air volume with exhaust air Hospitals are ‘plug and process load’ through a series of focus group meetings tracking to ensure the correct pressure intensive buildings. Heat gain from loads as with end-users of the medical equipment differential to the corridor they are used over the course of the day and specified for the project. This resulted in a Constant volume (fresh air requirement night, affect the sizing and operation of the more realistic concurrent peak heat gain only) with chilled ceilings mechanical cooling systems that maintain estimate. patient and staff comfort. Unlike typical Constant volume (fresh air requirement office equipment, diversified load The operating rooms proved to be a only) with chilled beams information for medical equipment is not particular challenge in terms of predicting readily available. Therefore, traditional equipment loads. Surgeons needed some of All systems studied used 100% outside air methods of accounting for heat gain from these rooms capable of cooling to 65ºF, – a choice which had already been shown to these loads is based on rules of thumb, while accommodating a significant quantity be cost-effective for other hospitals in the together with conservative safety factors or a of diagnostic equipment. Working with San Francisco Bay Area and greatly reduces summation of name plate power rating. clinical staff, the engineering team created a the risk of airborne infection transfer. spreadsheet of all the equipment with heat Overestimating loads results in unnecessarily gain and diversity factors estimated. Each system was analysed with different large ductwork, excessive and under-used Computational Fluid Dynamics (CFD) was heat recovery options. Variable air volume airflow capacity and mechanical systems used to model two different air supply with run-around coil heat recovery had the running at non-optimal, part-load conditions strategies to check for minimum turbulence best lifecycle cost performance for the most of the time. Seeing the opportunity for over the operating table. hospital, saving more than $3m over the energy savings, the engineering team studied presumed 20-year life of the system, the equipment heat gain using purchase order For patient rooms, three alternate air supply initial investment costs being recovered equipment cut-sheets, coupled with time-of- systems were studied and compared with the within 12.5 years. use or concurrent-use diversity factors. typical constant volume-reheat systems seen in typical US hospitals:

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93780_Text.indd 62 22/05/2015 10:36 Renewable energy Generating clean energy on-site was a project goal from the outset and the project team recommended 54 photovoltaic arrays with a total connected capacity of 500kW.

They developed a design in which the trellises supporting these arrays have been carefully coordinated around air handling units, exhaust fans and other major rooftop equipment. When installed, the PV panels will provide a visual screening to the air-handling units and shade the roof to reduce summer temperatures at the air intakes.

Therapeutic design Green spaces at urban hospitals have become increasingly important. In many hospitals lots of patient rooms look on to roof areas typically filled with mechanical equipment. Converting these spaces into rooftop gardens improves the view, but complicates mechanical designs.

At Mission Bay, the buildings are terraced to provide outdoor access at virtually every floor. The extent of rooftop green space is amongst the highest of any urban hospital in the US. There are 24 separate gardens and outdoor areas of respite providing a total green space of more than 1.1 acres on the roofs and 3.2 acres on the ground. 5.

The most important aspect of these roof Planting the roofs with gardens provided gardens is accessibility. At a pediatric added benefits in terms of handling hospital providing respite for the parents is stormwater. Stormwater draining from a especially important. At Mission Bay, green roof has higher water quality than that gardens and outdoor areas of respite are coming out of a typical on-grade bioswale integrated at almost every nursing unit on and the flow of stormwater from a roof every floor. garden is slowed, eliminating the need for a retention tank. The result is reduced impact Adding therapeutic garden spaces does, on San Francisco’s city storm-water system. however, increase potable water use. In locations with adequate rainfall – or consistent rain throughout the year – 4. rainwater collection strategies are adequate. But in dry climates or climates with long dry 3. Heat gain from equipment loads seasons – such as that in San Francisco – in operating rooms was assessed rainwater collection becomes untenable due and managed. to large tank requirements. 4. Clean energy will be generated on-site from photovoltaic arrays on To resolve this problem at Mission Bay, the roof. the design team used the cooling tower 5. Younger patients and visitors can blow-down as an irrigation water source enjoy well-planned play areas. with minimal extra filtration and some dilution, saving almost 3.5 million litres of potable water per year.

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93780_Text.indd 63 22/05/2015 10:36 Integrated delivery Integrated Project Delivery (IPD) is fast emerging as a proven approach for efficiently designing and constructing large projects. Mostly used in the private sector, it has been comparatively unusual in a public service context. However, UCSF decided on this route for its project, adopting an integrated and highly collaborative approach, combined with Building Information Modeling (BIM).

Based on the best value selection process, DPR Construction was awarded the project in 2008 and 13 key subcontractors for disciplines including MEP, structural steel, precast, exterior glazing, fire and fire alarm, drywall, pneumatic tube, elevators, and control were brought on board. This 6. integrated, collaborative team approach was to be a distinctive feature of the project.

BIM Clusters Project controls Project leadership production Integrated Center for Design and teams Construction (ICDC) Site In early 2009, the team initiated the creation 1 Hospital Budget of a virtual organisation, which included the Structural major subcontractors for MEP, drywall and

Exterior Cost concrete. A traditional approach of wall management completing design and then cutting costs OPB 2 Mechanical/ to meet budget was replaced with an plumbing Senior integrated effort to find opportunities to Planning leadership Electrical/ reduce costs through a collaborative low voltage process based on specific cost targets by EC 3 Special trade. Teams ‘virtually constructed’ the systems Schedule building looking for ways to optimise coordination, prefabrication and productivity Interiors and lean processes. Site Sustainability 4 Equipment A detailed three-dimensional model was created using BIM. Costs were reduced without reducing performance and the 7. schedule was managed through target costing and the use of Last Planner™ 6. An aerial view of the building. techniques. 7. Integrated Project Delivery and BIM meant the project was delivered With the virtual organisation established, exactly on schedule. UCSF opened the ICDC. Located on the 8. Maximising daylight and views Mission Bay site, the ICDC hosted more and minimising solar gain were than 250 people from 19 firms including mutually dependent objectives, architects, engineers, contractors, project successfully met. staff and subcontractors, working as one highly integrated team rather than individually and sequentially.

The co-location of project participants 8. enhanced collaboration and meant questions were answered and issues resolved quickly and efficiently. In fact, the project team surpassed its goal of getting 60% of questions answered in less than 20 minutes.

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93780_Text.indd 64 22/05/2015 10:36 9. A BIM diagram. There was a slightly more traditional For instance, sound attenuators were 10. High performance glazing and approach to the electrical discipline originally designed into the ductwork to external shades are key to energy drawings. All circuiting was done by the limit transmission of noise between the management and thermal comfort. design engineer but along the same rooms. However, when all items were project timeline. reflected in BIM to the level of detail required, it emerged that sound attenuators The design team had to schedule their work were unnecessary to meet the sound effort to match the construction sequence. requirement of the project. Eliminating them Completing detailed design and construction saved nearly $1m. documents in small, 25,000-square-foot batches meant that areas needed to be Another PMI was submitted when the complete from an architectural design process showed that the planned fire alarm standpoint prior to the detailed BIM effort system had voice-announcing capabilities starting. This created a major shift in the and could be used instead of purchasing a way designs were completed. separate public announcement system.

This process, and the level of detail required, The team reached the cost savings target six revealed unnecessary waste much earlier so months ahead of schedule. Approximately that the issue could be resolved in BIM well 280 PMIs were identified including .9. in advance of an in-the-field construction eliminating redundant items, finding more plan being set in motion. efficient ways to route pipes and conduit and identifying opportunities to take advantage Last Planner™ BIM techniques were used Target costing of market conditions in purchasing. weekly to identify upcoming commitments, One of the ICDC’s early goals was to find actions and other items - a date was assigned ways to reduce project costs using a tracking Contractors and engineers working side-by- for each - and the outcomes were tracked to system called Project Modification or side identified opportunities to prefabricate determine whether or not commitments were Innovation (PMI). Unlike value engineering, components or even sections of the facility, met. Well-run traditional projects improve to which reduces costs by potentially reducing such as walls with piping and conduit, a commitment rate of 70 to 75% whereas the the scope of the design, PMIs reduce waste leading to reduced material and labour costs, UCSF team regularly exceeded its target of by finding more efficient ways to meet the less waste and increased productivity for meeting 80% of commitments or more. scope of the design and thus reduce costs. the project.

Detailed BIM Because a number of key subcontractors were brought into the process nearly two years prior to the start of construction, the project team carried out a virtual build of the hospital, energy center and outpatient building complex in a fully detailed BIM model during the Construction Documents (CD) phase.

BIM for the project consisted of all studs, including king studs, all seismic supports and every piece of backing – levels of detail far beyond the normal coordination and clash detection conducted at the design stage.

For the mechanical (HVAC) trades, it made most sense for the contractors to own the building model and for Arup engineers to document other drawings and specifications, including equipment schedules, details and notes. The team then worked out dates when the mechanical engineers would provide the mechanical contractors with HVAC load calculations, including airflows and terminal box zoning diagrams for each 10. area of each building.

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93780_Text.indd 65 22/05/2015 10:36 11. UCSF Medical Center at Mission Bay provides comprehensive services in an environment centred on the compassionate care of patients and their families.

Authors Alisdair McGregor, Principal and Arup Fellow, was Project Director. Raj Daswani, Principal, Arup, was Project Director.

Project credits Client: University of California Architect: Stantec Architecture Associate Architect: William McDonough & Partners JV Consortium Partner and Structural Engineer: Rutherford & Chekene Main Contractor: DPR Construction Inc Specialist Consultant: McDonough, Braungart Design Chemistry Services and Structural Engineer: Arup – Kyle Adams, Shakeel Ahmed, Ibbi Almufti, Jesus Alvarez, Sergio Andermann, Austin Anderson, Key Anderson, Jason Arcilla, Alex Arnold, Candice Avanes, Raza Baqai Matt Baxley, David Bierman, Juanito Boado, Anna Bukareva- Padlo, Ramon Catiis, Michelle Chen, Kyle Chin, Susie Cho, Yen Chong, Kevin Clinch Joseph Collins, Kirk Crowther, Nancy Damore, Raj Daswani, Andrew Deves, Ranka Diklic, Michael Dimmel, Abdullah Drake El, Larry Encarnacion, Val Espinosa, Fang Fang, Anthony Fresquez, Jonathan Gervais, Nikki Gibson, Alex Goldsbrough, Pawel Gotlib, Stephanie Gulliver, Geoff Gunn, Irene Heung, Marshall Hilton Nicolas Hoffstetter, Jian Jin Guan, Masami Jin, Ramon Johnson II, Jacob Johnston, Gene Joves, Derek Kan, Taylor Keep, Galina Khalameyzer, Natalia Khaldi, Julie Kirkpatrick, Eric Ko, Jan-Peter Koppitz, Jason Krolicki, Lukki Lam, 11. Shaun Landman, Peter Lassetter, Jun Lautan, Christine Lee, Jackie Lee, Kathryn Lee, Yong Lim, Dee Lindsey, Keys to success Conclusion Anna Liu, Lanfang Liu, Siu-Ting Mak, Ruben Martinez, Lucy Mattingly, Bryan McCaffrey Nora McCawley, There were many benefits to the integrated Achieving sustainability in large hospitals Maurya Mcclintock, Alisdair McGregor, Ozzie approach compared with traditional project requires a leadership level of commitment Mercado, Janice Mochizuki, Afaan Naqvi, Gregory delivery. Chief amongst them were: from the owner and the UCSF team clearly Nielsen, Ciaran O’Donovan Michael Pang, Dylan demonstrated this. It also requires a holistic Pavelko, Quinn Peck, Vincent Pianalto, Todd Ravenscroft, Andrew Rhodes, Benedicte Riis-Duryea, Producing a fully BIM-coordinated set of approach and a clear plan that integrates Susannah Rivera, Tina Sack Don Sarmiento, Ankit documents prior to construction bid, which sustainable concepts into all aspects of the Sethi, Nick Sherrow-Groves, Darren Sri-Tharan, Mark helped reduce risks of costs and delays project from the start of the project, and this Stansbury, Jenna Stauffer, Paul Switenki, Geza Szakats, was achieved through the ICDC. Sin-Tsuen Tong, Neil Tooch, Aldrin Tordecilla, Sherry Identifying more opportunities for Ung, Ben Waters, Christopher Werring, Armin Wolski, prefabrication Eric Wong, Dick Wong, John Worley, Roddy Wykes, Liu In January 2015, UCSF Medical Center at Yang, Tom Yim, Serena Zhu. • Reducing the inefficiencies inherent in Mission Bay, became one of the first Alisdair McGregor and Raj Daswani wish to thank the coordinating a set of documents after bid hospitals in California to be awarded LEED following people for providing input to this article: Gold Certification (Leadership in Energy Stuart Eckblad is the Executive Director of Design and The most significant change, however, was and Environmental Design). Construction for UCSF Medical Center at Mission Bay in the mind shift required from each team and a licensed architect in California; George Pfeffer, member. Instead of designing in small Executive Vice President for DPR Construction, is the It is a further tribute to the success of this Project Executive for the UCSF Medical Center at batches, they had to think in terms of project that the UCSF Medical Center at Mission Bay integrated delivery project; Ann Killeen, completing a zone at a time with the Mission Bay received its certification of AIA, is the Principal-in-Charge of the UCSF Medical submittal process being derived from the completion eight days early and opened to Center at Mission Bay project for Stantec, Architecture. production schedule. They were successful patients on 1 February 2015, on the target She is also the Managing Principal of the San Francisco office of Stantec; Tyler Krehlik, AIA, LEED in this. In the ICDC everyone committed to date set six years previously. AP was the sustainability chair at Stantec Architecture, working together as a virtual integrated San Francisco. He now works for Smith Group; organisation to achieve optimum results for a Afaan Naqvi, is a senior mechanical engineer in Arup’s world-class project, setting new standards in San Francisco office with a strong interest in energy project delivery. performance of building and campus level systems. Image credits 1 UCSF/Mark Citret; 4, 6 UCSF, 11 UCSF/Brooke Duthie; 2, 3, 5, 8, 10 Stantec and Rien van Rijthoven; 7, 9 DPR Construction.

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93780_Text.indd 66 22/05/2015 10:36 93780_Cover.indd 2 22/05/2015 10:32 The Arup Journal The Arup Issue 1 2015 The Arup Journal About Arup

Arup is a global organisation of designers, Arup’s core values drive a strong culture Printed by Pureprint Group using engineers, planners, and business of sharing and collaboration. their ® environmental print consultants, founded in 1946 by Sir Ove technology. The printing inks are made from vegetable based oils and Arup (1895-1988). It has a constantly All this results in: no harmful industrial alcohol is used evolving skills base, and works with local a dynamic working environment that in the printing process with 98% of and international clients around the world. any dry waste associated with this inspires creativity and innovation production diverted from landfill. ® a commitment to the environment and the Pureprint Group is a CarbonNeutral Arup is owned by Trusts established for the company and is certificated to benefit of its staff and for charitable communities where we work that defines Environmental Management purposes, with no external shareholders. our approach to work, to clients and System ISO 14001 and registered This ownership structure, together with the collaborators, and to our own members to EMAS, the Eco Management and Audit Scheme. core values set down by Sir Ove Arup, robust professional and personal networks are fundamental to the way the firm is that are reinforced by positive policies on organised and operates. The Arup Journal equality, fairness, staff mobility, and Vol50 No1 (1/2015) knowledge sharing Editor: Angela Swann Independence enables Arup to: Designer: Nigel Whale the ability to grow organically by attracting shape its own direction and take a long- Editorial: Tel: +44 (0)20 7755 4838 and retaining the best and brightest email: [email protected] term view, unhampered by short-term individuals from around the world – and pressures from external shareholders Published by Global Marketing from a broad range of cultures – who share and Communications, distribute its profits through reinvestment those core values and beliefs in social Arup, 13 Fitzroy Street, in learning, research and development, to usefulness, sustainable development, and London W1T 4BQ, UK. Tel: +44 (0)20 7636 1531 staff through a global profit-sharing excellence in the quality of our work. Fax: +44 (0)20 7580 3924 scheme, and by donation to charitable All articles ©Arup 2015 organisations. With this combination of global reach and a collaborative approach that is values-driven, Arup is uniquely positioned to fulfil its aim to shape a better world. Issue 1 2015

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